| /* i1401_cpu.c: IBM 1401 CPU simulator | |
| Copyright (c) 1993-2012, Robert M. Supnik | |
| Permission is hereby granted, free of charge, to any person obtaining a | |
| copy of this software and associated documentation files (the "Software"), | |
| to deal in the Software without restriction, including without limitation | |
| the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
| and/or sell copies of the Software, and to permit persons to whom the | |
| Software is furnished to do so, subject to the following conditions: | |
| The above copyright notice and this permission notice shall be included in | |
| all copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
| ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER | |
| IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
| CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
| Except as contained in this notice, the name of Robert M Supnik shall not be | |
| used in advertising or otherwise to promote the sale, use or other dealings | |
| in this Software without prior written authorization from Robert M Supnik. | |
| 08-Oct-12 RMS Clear storage and branch preserves B register (Van Snyder) | |
| 19-Mar-11 RMS Reverted multiple tape indicator implementation | |
| 20-Jan-11 RMS Fixed branch on EOT indicator per hardware (Van Snyder) | |
| 07-Nov-10 RMS Fixed divide not to clear word marks in quotient | |
| 24-Apr-10 RMS Revised divide algorithm (Van Snyder) | |
| 11-Jul-08 RMS Added missing A magtape modifier (Van Snyder) | |
| Fixed tape indicator implementation (Bob Abeles) | |
| Fixed bug in ZA and ZS (Bob Abeles) | |
| 07-Jul-07 RMS Removed restriction on load-mode binary tape | |
| 28-Jun-07 RMS Added support for SS overlap modifiers | |
| 22-May-06 RMS Fixed format error in CPU history (Peter Schorn) | |
| 06-Mar-06 RMS Fixed bug in divide (Van Snyder) | |
| 22-Sep-05 RMS Fixed declarations (Sterling Garwood) | |
| 01-Sep-05 RMS Removed error stops in MCE | |
| 16-Aug-05 RMS Fixed C++ declaration and cast problems | |
| 02-Jun-05 RMS Fixed SSB-SSG clearing on RESET | |
| (Ralph Reinke) | |
| 14-Nov-04 WVS Added column binary support, debug support | |
| 06-Nov-04 RMS Added instruction history | |
| 12-Jul-03 RMS Moved ASCII/BCD tables to included file | |
| Revised fetch to model hardware | |
| Removed length checking in fetch phase | |
| 16-Mar-03 RMS Fixed mnemonic, instruction lengths, and reverse | |
| scan length check bug for MCS | |
| Fixed MCE bug, BS off by 1 if zero suppress | |
| Fixed chaining bug, D lost if return to SCP | |
| Fixed H branch, branch occurs after continue | |
| Added check for invalid 8 character MCW, LCA | |
| 03-Jun-03 RMS Added 1311 support | |
| 22-May-02 RMS Added multiply and divide | |
| 30-Dec-01 RMS Added old PC queue | |
| 30-Nov-01 RMS Added extended SET/SHOW support | |
| 10-Aug-01 RMS Removed register in declarations | |
| 07-Dec-00 RMS Fixed bugs found by Charles Owen | |
| -- 4,7 char NOPs are legal | |
| -- 1 char B is chained BCE | |
| -- MCE moves whole char after first | |
| 14-Apr-99 RMS Changed t_addr to unsigned | |
| The register state for the IBM 1401 is: | |
| IS I storage address register (PC) | |
| AS A storage address register (address of first operand) | |
| BS B storage address register (address of second operand) | |
| ind[0:63] indicators | |
| SSA sense switch A | |
| IOCHK I/O check | |
| PRCHK process check | |
| The IBM 1401 is a variable instruction length, decimal data system. | |
| Memory consists of 4000, 8000, 12000, or 16000 BCD characters, each | |
| containing six bits of data and a word mark. There are no general | |
| registers; all instructions are memory to memory, using explicit | |
| addresses or an address pointer from a prior instruction. | |
| BCD numeric data consists of the low four bits of a character (DIGIT), | |
| encoded as X, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, X, X, X, X, X. The high | |
| two bits (ZONE) encode the sign of the data as +, +, -, +. Character | |
| data uses all six bits of a character. Numeric and character fields are | |
| delimited by a word mark. Fields are typically processed in descending | |
| address order (low-order data to high-order data). | |
| The 1401 encodes a decimal address, and an index register number, in | |
| three characters: | |
| character zone digit | |
| addr + 0 <1:0> of thousands hundreds | |
| addr + 1 index register # tens | |
| addr + 2 <3:2> of thousands ones | |
| Normally the digit values 0, 11, 12, 13, 14, 15 are illegal in addresses. | |
| However, in indexing, digits are passed through the adder, and illegal | |
| values are normalized to legal counterparts. | |
| The 1401 has six instruction formats: | |
| op A and B addresses, if any, from AS and BS | |
| op d A and B addresses, if any, from AS and BS | |
| op aaa B address, if any, from BS | |
| op aaa d B address, if any, from BS | |
| op aaa bbb | |
| op aaa bbb d | |
| where aaa is the A address, bbb is the B address, and d is a modifier. | |
| The opcode has word mark set; all other characters have word mark clear. | |
| This routine is the instruction decode routine for the IBM 1401. | |
| It is called from the simulator control program to execute | |
| instructions in simulated memory, starting at the simulated PC. | |
| It runs until 'reason' is set non-zero. | |
| General notes: | |
| 1. Reasons to stop. The simulator can be stopped by: | |
| HALT instruction | |
| breakpoint encountered | |
| illegal addresses or instruction formats | |
| I/O error in I/O simulator | |
| 2. Interrupts. The 1401 has no interrupt structure. | |
| 3. Non-existent memory. On the 1401, references to non-existent | |
| memory halt the processor. | |
| 4. Adding I/O devices. These modules must be modified: | |
| i1401_cpu.c add device dispatching code to iodisp | |
| i1401_sys.c add sim_devices table entry | |
| */ | |
| #include "i1401_defs.h" | |
| #include "i1401_dat.h" | |
| #define PCQ_SIZE 64 /* must be 2**n */ | |
| #define PCQ_MASK (PCQ_SIZE - 1) | |
| #define PCQ_ENTRY pcq[pcq_p = (pcq_p - 1) & PCQ_MASK] = saved_IS | |
| #define HIST_MIN 64 | |
| #define HIST_MAX 65536 | |
| typedef struct { | |
| uint16 is; | |
| uint16 ilnt; | |
| uint8 inst[MAX_L]; | |
| } InstHistory; | |
| /* These macros validate addresses. If an addresses error is detected, | |
| they return an error status to the caller. These macros should only | |
| be used in a routine that returns a t_stat value. | |
| */ | |
| #define MM(x) x = x - 1; \ | |
| if (x < 0) { \ | |
| x = BA + MAXMEMSIZE - 1; \ | |
| reason = STOP_WRAP; \ | |
| break; \ | |
| } | |
| #define PP(x) x = x + 1; \ | |
| if (ADDR_ERR (x)) { \ | |
| x = BA + (x % MAXMEMSIZE); \ | |
| reason = STOP_WRAP; \ | |
| break; \ | |
| } | |
| #define BRANCH if (ADDR_ERR (AS)) { \ | |
| reason = STOP_INVBR; \ | |
| break; \ | |
| } \ | |
| if (cpu_unit.flags & XSA) \ | |
| BS = IS; \ | |
| else BS = BA + 0; \ | |
| PCQ_ENTRY; \ | |
| IS = AS; | |
| #define BRANCH_CS if (ADDR_ERR (AS)) { \ | |
| reason = STOP_INVBR; \ | |
| break; \ | |
| } \ | |
| PCQ_ENTRY; \ | |
| IS = AS; | |
| uint8 M[MAXMEMSIZE] = { 0 }; /* main memory */ | |
| int32 saved_IS = 0; /* saved IS */ | |
| int32 AS = 0; /* AS */ | |
| int32 BS = 0; /* BS */ | |
| int32 D = 0; /* modifier */ | |
| int32 as_err = 0, bs_err = 0; /* error flags */ | |
| int32 hb_pend = 0; /* halt br pending */ | |
| uint16 pcq[PCQ_SIZE] = { 0 }; /* PC queue */ | |
| int32 pcq_p = 0; /* PC queue ptr */ | |
| REG *pcq_r = NULL; /* PC queue reg ptr */ | |
| int32 ind[64] = { 0 }; /* indicators */ | |
| int32 ssa = 1; /* sense switch A */ | |
| int32 prchk = 0; /* process check stop */ | |
| int32 iochk = 0; /* I/O check stop */ | |
| int32 hst_p = 0; /* history pointer */ | |
| int32 hst_lnt = 0; /* history length */ | |
| InstHistory *hst = NULL; /* instruction history */ | |
| t_bool conv_old = 0; /* old conversions */ | |
| extern int32 sim_emax; | |
| extern t_value *sim_eval; | |
| t_stat cpu_ex (t_value *vptr, t_addr addr, UNIT *uptr, int32 sw); | |
| t_stat cpu_dep (t_value val, t_addr addr, UNIT *uptr, int32 sw); | |
| t_stat cpu_reset (DEVICE *dptr); | |
| t_stat cpu_set_size (UNIT *uptr, int32 val, char *cptr, void *desc); | |
| t_stat cpu_set_hist (UNIT *uptr, int32 val, char *cptr, void *desc); | |
| t_stat cpu_show_hist (FILE *st, UNIT *uptr, int32 val, void *desc); | |
| t_stat cpu_set_conv (UNIT *uptr, int32 val, char *cptr, void *desc); | |
| t_stat cpu_show_conv (FILE *st, UNIT *uptr, int32 val, void *desc); | |
| int32 store_addr_h (int32 addr); | |
| int32 store_addr_t (int32 addr); | |
| int32 store_addr_u (int32 addr); | |
| int32 div_add (int32 ap, int32 bp); | |
| int32 div_sub (int32 ap, int32 bp); | |
| void div_sign (int32 dvrc, int32 dvdc, int32 qp, int32 rp); | |
| t_stat iomod (int32 ilnt, int32 mod, const int32 *tptr); | |
| t_stat iodisp (int32 dev, int32 unit, int32 flag, int32 mod); | |
| extern t_stat read_card (int32 ilnt, int32 mod); | |
| extern t_stat punch_card (int32 ilnt, int32 mod); | |
| extern t_stat select_stack (int32 mod); | |
| extern t_stat carriage_control (int32 mod); | |
| extern t_stat write_line (int32 ilnt, int32 mod); | |
| extern t_stat inq_io (int32 flag, int32 mod); | |
| extern t_stat mt_io (int32 unit, int32 flag, int32 mod); | |
| extern t_stat dp_io (int32 fnc, int32 flag, int32 mod); | |
| extern t_stat mt_func (int32 unit, int32 flag, int32 mod); | |
| /* CPU data structures | |
| cpu_dev CPU device descriptor | |
| cpu_unit CPU unit descriptor | |
| cpu_reg CPU register list | |
| cpu_mod CPU modifier list | |
| */ | |
| UNIT cpu_unit = { | |
| UDATA (NULL, UNIT_FIX + UNIT_BCD + STDOPT, MAXMEMSIZE) | |
| }; | |
| REG cpu_reg[] = { | |
| { DRDATA (IS, saved_IS, 14), PV_LEFT }, | |
| { DRDATA (AS, AS, 14), PV_LEFT }, | |
| { DRDATA (BS, BS, 14), PV_LEFT }, | |
| { FLDATA (ASERR, as_err, 0) }, | |
| { FLDATA (BSERR, bs_err, 0) }, | |
| { ORDATA (D, D, 7) }, | |
| { FLDATA (SSA, ssa, 0) }, | |
| { FLDATA (SSB, ind[IN_SSB], 0) }, | |
| { FLDATA (SSC, ind[IN_SSC], 0) }, | |
| { FLDATA (SSD, ind[IN_SSD], 0) }, | |
| { FLDATA (SSE, ind[IN_SSE], 0) }, | |
| { FLDATA (SSF, ind[IN_SSF], 0) }, | |
| { FLDATA (SSG, ind[IN_SSG], 0) }, | |
| { FLDATA (EQU, ind[IN_EQU], 0) }, | |
| { FLDATA (UNEQ, ind[IN_UNQ], 0) }, | |
| { FLDATA (HIGH, ind[IN_HGH], 0) }, | |
| { FLDATA (LOW, ind[IN_LOW], 0) }, | |
| { FLDATA (OVF, ind[IN_OVF], 0) }, | |
| { FLDATA (IOCHK, iochk, 0) }, | |
| { FLDATA (PRCHK, prchk, 0) }, | |
| { FLDATA (HBPEND, hb_pend, 0) }, | |
| { BRDATA (IND, ind, 8, 32, 64), REG_HIDDEN + PV_LEFT }, | |
| { BRDATA (ISQ, pcq, 10, 14, PCQ_SIZE), REG_RO+REG_CIRC }, | |
| { DRDATA (ISQP, pcq_p, 6), REG_HRO }, | |
| { ORDATA (WRU, sim_int_char, 8) }, | |
| { FLDATA (CONVOLD, conv_old, 0), REG_HIDDEN }, | |
| { NULL } | |
| }; | |
| MTAB cpu_mod[] = { | |
| { XSA, XSA, "XSA", "XSA", NULL }, | |
| { XSA, 0, "no XSA", "NOXSA", NULL }, | |
| { HLE, HLE, "HLE", "HLE", NULL }, | |
| { HLE, 0, "no HLE", "NOHLE", NULL }, | |
| { BBE, BBE, "BBE", "BBE", NULL }, | |
| { BBE, 0, "no BBE", "NOBBE", NULL }, | |
| { MA, MA, "MA", 0, NULL }, | |
| { MA, 0, "no MA", 0, NULL }, | |
| { MR, MR, "MR", "MR", NULL }, | |
| { MR, 0, "no MR", "NOMR", NULL }, | |
| { EPE, EPE, "EPE", "EPE", NULL }, | |
| { EPE, 0, "no EPE", "NOEPE", NULL }, | |
| { MDV, MDV, "MDV", "MDV", NULL }, | |
| { MDV, 0, "no MDV", "NOMDV", NULL }, | |
| { UNIT_MSIZE, 4000, NULL, "4K", &cpu_set_size }, | |
| { UNIT_MSIZE, 8000, NULL, "8K", &cpu_set_size }, | |
| { UNIT_MSIZE, 12000, NULL, "12K", &cpu_set_size }, | |
| { UNIT_MSIZE, 16000, NULL, "16K", &cpu_set_size }, | |
| { MTAB_XTD|MTAB_VDV|MTAB_NMO|MTAB_SHP, 0, "HISTORY", "HISTORY", | |
| &cpu_set_hist, &cpu_show_hist }, | |
| { MTAB_XTD|MTAB_VDV|MTAB_NMO, 0, "CONVERSIONS", "NEWCONVERSIONS", | |
| &cpu_set_conv, &cpu_show_conv }, | |
| { MTAB_XTD|MTAB_VDV|MTAB_NMO, 1, NULL, "OLDCONVERSIONS", | |
| &cpu_set_conv, NULL }, | |
| { 0 } | |
| }; | |
| DEVICE cpu_dev = { | |
| "CPU", &cpu_unit, cpu_reg, cpu_mod, | |
| 1, 10, 14, 1, 8, 7, | |
| &cpu_ex, &cpu_dep, &cpu_reset, | |
| NULL, NULL, NULL, | |
| NULL, DEV_DEBUG | |
| }; | |
| /* Tables */ | |
| /* Opcode table - length, dispatch, and option flags. This table is | |
| used by the symbolic input routine to validate instruction lengths */ | |
| const int32 op_table[64] = { | |
| 0, /* 00: illegal */ | |
| L1 | L2 | L4 | L5, /* read */ | |
| L1 | L2 | L4 | L5, /* write */ | |
| L1 | L2 | L4 | L5, /* write and read */ | |
| L1 | L2 | L4 | L5, /* punch */ | |
| L1 | L4, /* read and punch */ | |
| L1 | L2 | L4 | L5, /* write and read */ | |
| L1 | L2 | L4 | L5, /* write, read, punch */ | |
| L1, /* 10: read feed */ | |
| L1, /* punch feed */ | |
| 0, /* illegal */ | |
| L1 | L4 | L7 | AREQ | BREQ | MA, /* modify address */ | |
| L1 | L4 | L7 | AREQ | BREQ | MDV, /* multiply */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* 20: illegal */ | |
| L1 | L4 | L7 | BREQ | NOWM, /* clear storage */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* subtract */ | |
| 0, /* illegal */ | |
| L5 | IO, /* magtape */ | |
| L1 | L8 | BREQ, /* branch wm or zone */ | |
| L1 | L8 | BREQ | BBE, /* branch if bit eq */ | |
| 0, /* illegal */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* 30: move zones */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* move supress zero */ | |
| 0, /* illegal */ | |
| L1 | L4 | L7 | AREQ | BREQ | NOWM, /* set word mark */ | |
| L1 | L4 | L7 | AREQ | BREQ | MDV, /* divide */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* 40: illegal */ | |
| 0, /* illegal */ | |
| L2 | L5, /* select stacker */ | |
| L1 | L4 | L7 | L8 | BREQ | MLS | IO, /* load */ | |
| L1 | L4 | L7 | L8 | BREQ | MLS | IO, /* move */ | |
| HNOP | L1 | L2 | L4 | L5 | L7 | L8, /* nop */ | |
| 0, /* illegal */ | |
| L1 | L4 | L7 | AREQ | BREQ | MR, /* move to record */ | |
| L1 | L4 | AREQ | MLS, /* 50: store A addr */ | |
| 0, /* illegal */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* zero and subtract */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0, /* 60: illegal */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* add */ | |
| L1 | L4 | L5 | L8, /* branch */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* compare */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* move numeric */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* move char edit */ | |
| L2 | L5, /* carriage control */ | |
| 0, /* illegal */ | |
| L1 | L4 | L7 | AREQ | MLS, /* 70: store B addr */ | |
| 0, /* illegal */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* zero and add */ | |
| HNOP | L1 | L2 | L4 | L5 | L7 | L8, /* halt */ | |
| L1 | L4 | L7 | AREQ | BREQ, /* clear word mark */ | |
| 0, /* illegal */ | |
| 0, /* illegal */ | |
| 0 /* illegal */ | |
| }; | |
| const int32 len_table[9] = { 0, L1, L2, 0, L4, L5, 0, L7, L8 }; | |
| /* Address character conversion tables. Illegal characters are marked by | |
| the flag BA but also contain the post-adder value for indexing */ | |
| const int32 hun_table[64] = { | |
| BA+000, 100, 200, 300, 400, 500, 600, 700, | |
| 800, 900, 000, BA+300, BA+400, BA+500, BA+600, BA+700, | |
| BA+1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, | |
| 1800, 1900, 1000, BA+1300, BA+1400, BA+1500, BA+1600, BA+1700, | |
| BA+2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, | |
| 2800, 2900, 2000, BA+2300, BA+2400, BA+2500, BA+2600, BA+2700, | |
| BA+3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, | |
| 3800, 3900, 3000, BA+3300, BA+3400, BA+3500, BA+3600, BA+3700 | |
| }; | |
| const int32 ten_table[64] = { | |
| BA+00, 10, 20, 30, 40, 50, 60, 70, | |
| 80, 90, 00, BA+30, BA+40, BA+50, BA+60, BA+70, | |
| X1+00, X1+10, X1+20, X1+30, X1+40, X1+50, X1+60, X1+70, | |
| X1+80, X1+90, X1+00, X1+30, X1+40, X1+50, X1+60, X1+70, | |
| X2+00, X2+10, X2+20, X2+30, X2+40, X2+50, X2+60, X2+70, | |
| X2+80, X2+90, X2+00, X2+30, X2+40, X2+50, X2+60, X2+70, | |
| X3+00, X3+10, X3+20, X3+30, X3+40, X3+50, X3+60, X3+70, | |
| X3+80, X3+90, X3+00, X3+30, X3+40, X3+50, X3+60, X3+70 | |
| }; | |
| const int32 one_table[64] = { | |
| BA+0, 1, 2, 3, 4, 5, 6, 7, | |
| 8, 9, 0, BA+3, BA+4, BA+5, BA+6, BA+7, | |
| BA+4000, 4001, 4002, 4003, 4004, 4005, 4006, 4007, | |
| 4008, 4009, 4000, BA+4003, BA+4004, BA+4005, BA+4006, BA+4007, | |
| BA+8000, 8001, 8002, 8003, 8004, 8005, 8006, 8007, | |
| 8008, 8009, 8000, BA+8003, BA+8004, BA+8005, BA+8006, BA+8007, | |
| BA+12000, 12001, 12002, 12003, 12004, 12005, 12006, 12007, | |
| 12008, 12009, 12000, BA+12003, BA+12004, BA+12005, BA+12006, BA+12007 | |
| }; | |
| const int32 bin_to_bcd[16] = { | |
| 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 | |
| }; | |
| const int32 bcd_to_bin[16] = { | |
| 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 3, 4, 5, 6, 7 | |
| }; | |
| /* Indicator resets - a 1 marks an indicator that resets when tested */ | |
| static const int32 ind_table[64] = { | |
| 0, 0, 0, 0, 0, 0, 0, 0, /* 00 - 07 */ | |
| 0, 0, 0, 0, 0, 0, 0, 0, /* 10 - 17 */ | |
| 0, 0, 0, 0, 0, 0, 0, 0, /* 20 - 27 */ | |
| 0, 1, 1, 0, 1, 0, 0, 0, /* 30 - 37 */ | |
| 0, 0, 0, 0, 0, 0, 0, 0, /* 40 - 47 */ | |
| 0, 0, 1, 0, 1, 0, 0, 0, /* 50 - 57 */ | |
| 0, 0, 0, 0, 0, 0, 0, 0, /* 60 - 67 */ | |
| 0, 0, 1, 0, 0, 0, 0, 0 /* 70 - 77 */ | |
| }; | |
| /* Character collation table for compare with HLE option */ | |
| static const int32 col_table[64] = { | |
| 000, 067, 070, 071, 072, 073, 074, 075, | |
| 076, 077, 066, 024, 025, 026, 027, 030, | |
| 023, 015, 056, 057, 060, 061, 062, 063, | |
| 064, 065, 055, 016, 017, 020, 021, 022, | |
| 014, 044, 045, 046, 047, 050, 051, 052, | |
| 053, 054, 043, 007, 010, 011, 012, 013, | |
| 006, 032, 033, 034, 035, 036, 037, 040, | |
| 041, 042, 031, 001, 002, 003, 004, 005 | |
| }; | |
| /* Summing table for two decimal digits, converted back to BCD | |
| Also used for multiplying two decimal digits, converted back to BCD, | |
| with carry forward | |
| */ | |
| static const int32 sum_table[100] = { | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE, | |
| BCD_ZERO, BCD_ONE, BCD_TWO, BCD_THREE, BCD_FOUR, | |
| BCD_FIVE, BCD_SIX, BCD_SEVEN, BCD_EIGHT, BCD_NINE | |
| }; | |
| static const int32 cry_table[100] = { | |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | |
| 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | |
| 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, | |
| 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, | |
| 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, | |
| 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, | |
| 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, | |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
| 9, 9, 9, 9, 9, 9, 9, 9, 9, 9 | |
| }; | |
| /* Legal modifier tables */ | |
| static const int32 r_mod[] = { | |
| BCD_C, -1 | |
| }; | |
| static const int32 p_mod[] = { | |
| BCD_C, -1 | |
| }; | |
| static const int32 w_mod[] = { | |
| BCD_S, BCD_SQUARE, -1 | |
| }; | |
| static const int32 ss_mod[] = { | |
| BCD_ONE, BCD_TWO, BCD_FOUR, BCD_EIGHT, | |
| BCD_DOLLAR, BCD_DECIMAL, BCD_SQUARE, -1 | |
| }; | |
| static const int32 mtf_mod[] = { | |
| BCD_A, BCD_B, BCD_E, | |
| BCD_M, BCD_R, BCD_U, -1 | |
| }; | |
| t_stat sim_instr (void) | |
| { | |
| int32 IS, ilnt, flags; | |
| int32 op, xa, t, wm, ioind, dev, unit; | |
| int32 a, b, i, k, asave, bsave; | |
| int32 carry, lowprd, sign, ps; | |
| int32 quo, qs; | |
| int32 qzero, qawm, qbody, qsign, qdollar, qaster, qdecimal; | |
| t_stat reason, r1, r2; | |
| /* Restore saved state */ | |
| IS = saved_IS; | |
| if (as_err) /* flag bad addresses */ | |
| AS = AS | BA; | |
| if (bs_err) | |
| BS = BS | BA; | |
| as_err = bs_err = 0; /* reset error flags */ | |
| reason = 0; | |
| /* Main instruction fetch/decode loop */ | |
| while (reason == 0) { /* loop until halted */ | |
| if (hb_pend) { /* halt br pending? */ | |
| hb_pend = 0; /* clear flag */ | |
| BRANCH; /* execute branch */ | |
| } | |
| saved_IS = IS; /* commit prev instr */ | |
| if (sim_interval <= 0) { /* check clock queue */ | |
| /* make sure all useful state is in simh registers while processing events */ | |
| as_err = ADDR_ERR (AS); /* get addr err flags */ | |
| bs_err = ADDR_ERR (BS); | |
| AS = AS & ADDRMASK; /* clean addresses */ | |
| BS = BS & ADDRMASK; | |
| pcq_r->qptr = pcq_p; /* update pc q ptr */ | |
| if ((reason = sim_process_event ())) | |
| break; | |
| } | |
| if (sim_brk_summ && sim_brk_test (IS, SWMASK ('E'))) { /* breakpoint? */ | |
| reason = STOP_IBKPT; /* stop simulation */ | |
| break; | |
| } | |
| sim_interval = sim_interval - 1; | |
| /* Instruction fetch - 1401 fetch works as follows: | |
| - Each character fetched enters the B register. This register is not | |
| visible; the variable t represents the B register. | |
| - Except for the first and last cycles, each character fetched enters | |
| the A register. This register is not visible; the variable D represents | |
| the A register, because this is the instruction modifier for 2, 5, and 8 | |
| character instructions. | |
| - At the start of the second cycle (first address character), the A-address | |
| register and, for most instructions, the B-address register, are cleared | |
| to blanks. The simulator represents addresses in binary and creates the | |
| effect of blanks (address is bad) if less than three A-address characters | |
| are found. Further, the simulator accumulates only the A-address, and | |
| replicates it to the B-address at the appropriate point. | |
| - At the start of the fifth cycle (fourth address character), the B-address | |
| register is cleared to blanks. Again, the simulator creates the effect of | |
| blanks (address is bad) if less than three B-address characters are found. | |
| The 1401 does not explicitly check for valid instruction lengths. Most 2, | |
| 3, 5, 6 character instructions will be invalid because the A-address or | |
| B-address (or both) are invalid. | |
| */ | |
| if ((M[IS] & WM) == 0) { /* I-Op: WM under op? */ | |
| reason = STOP_NOWM; /* no, error */ | |
| break; | |
| } | |
| op = M[IS] & CHAR; /* get opcode */ | |
| flags = op_table[op]; /* get op flags */ | |
| if ((flags == 0) || (flags & ALLOPT & ~cpu_unit.flags)) { | |
| reason = STOP_NXI; /* illegal inst? */ | |
| break; | |
| } | |
| if (op == OP_SAR) /* SAR? save ASTAR */ | |
| BS = AS; | |
| PP (IS); | |
| if ((t = M[IS]) & WM) /* I-1: WM? 1 char inst */ | |
| goto CHECK_LENGTH; | |
| D = ioind = t; /* could be D char, % */ | |
| AS = hun_table[t]; /* could be A addr */ | |
| PP (IS); /* if %xy, BA is set */ | |
| if ((t = M[IS]) & WM) { /* I-2: WM? 2 char inst */ | |
| AS = AS | BA; /* ASTAR bad */ | |
| if (!(flags & MLS)) | |
| BS = AS; | |
| goto CHECK_LENGTH; | |
| } | |
| D = dev = t; /* could be D char, dev */ | |
| AS = AS + ten_table[t]; /* build A addr */ | |
| PP (IS); | |
| if ((t = M[IS]) & WM) { /* I-3: WM? 3 char inst */ | |
| AS = AS | BA; /* ASTAR bad */ | |
| if (!(flags & MLS)) | |
| BS = AS; | |
| goto CHECK_LENGTH; | |
| } | |
| D = unit = t; /* could be D char, unit */ | |
| if (unit == BCD_ZERO) /* convert unit to binary */ | |
| unit = 0; | |
| AS = AS + one_table[t]; /* finish A addr */ | |
| xa = (AS >> V_INDEX) & M_INDEX; /* get index reg */ | |
| if (xa && (ioind != BCD_PERCNT) && (cpu_unit.flags & XSA)) { /* indexed? */ | |
| AS = AS + hun_table[M[xa] & CHAR] + ten_table[M[xa + 1] & CHAR] + | |
| one_table[M[xa + 2] & CHAR]; | |
| AS = (AS & INDEXMASK) % MAXMEMSIZE; | |
| } | |
| if (!(flags & MLS)) /* not MLS? B = A */ | |
| BS = AS; | |
| PP (IS); | |
| if ((t = M[IS]) & WM) /* I-4: WM? 4 char inst */ | |
| goto CHECK_LENGTH; | |
| if ((op == OP_B) && (t == BCD_BLANK)) /* BR + space? */ | |
| goto CHECK_LENGTH; | |
| D = t; /* could be D char */ | |
| BS = hun_table[t]; /* could be B addr */ | |
| PP (IS); | |
| if ((t = M[IS]) & WM) { /* I-5: WM? 5 char inst */ | |
| BS = BS | BA; /* BSTAR bad */ | |
| goto CHECK_LENGTH; | |
| } | |
| D = t; /* could be D char */ | |
| BS = BS + ten_table[t]; /* build B addr */ | |
| PP (IS); | |
| if ((t = M[IS]) & WM) { /* I-6: WM? 6 char inst */ | |
| BS = BS | BA; /* BSTAR bad */ | |
| goto CHECK_LENGTH; | |
| } | |
| D = t; /* could be D char */ | |
| BS = BS + one_table[t]; /* finish B addr */ | |
| xa = (BS >> V_INDEX) & M_INDEX; /* get index reg */ | |
| if (xa && (cpu_unit.flags & XSA)) { /* indexed? */ | |
| BS = BS + hun_table[M[xa] & CHAR] + ten_table[M[xa + 1] & CHAR] + | |
| one_table[M[xa + 2] & CHAR]; | |
| BS = (BS & INDEXMASK) % MAXMEMSIZE; | |
| } | |
| PP (IS); | |
| if (flags & NOWM) /* I-7: SWM? done */ | |
| goto CHECK_LENGTH; | |
| if ((t = M[IS]) & WM) /* WM? 7 char inst */ | |
| goto CHECK_LENGTH; | |
| D = t; /* last char is D */ | |
| while (((t = M[IS]) & WM) == 0) { /* I-8: repeats until WM */ | |
| D = t; /* last char is D */ | |
| PP (IS); | |
| } | |
| if (reason) /* addr err on last? */ | |
| break; | |
| CHECK_LENGTH: | |
| if ((flags & BREQ) && ADDR_ERR (BS)) { /* valid B? */ | |
| reason = STOP_INVB; | |
| break; | |
| } | |
| if ((flags & AREQ) && ADDR_ERR (AS)) { /* valid A? */ | |
| reason = STOP_INVA; | |
| break; | |
| } | |
| ilnt = IS - saved_IS; /* get lnt */ | |
| if (hst_lnt) { /* history enabled? */ | |
| hst_p = (hst_p + 1); /* next entry */ | |
| if (hst_p >= hst_lnt) | |
| hst_p = 0; | |
| hst[hst_p].is = saved_IS; /* save IS */ | |
| hst[hst_p].ilnt = ilnt; | |
| for (i = 0; (i < MAX_L) && (i < ilnt); i++) | |
| hst[hst_p].inst[i] = M[saved_IS + i]; | |
| } | |
| if (DEBUG_PRS (cpu_dev)) { | |
| fprint_val (sim_deb, saved_IS, 10, 5, PV_RSPC); | |
| fprintf (sim_deb, ": " ); | |
| for (i = 0; i < sim_emax; i++) | |
| sim_eval[i] = 0; | |
| for (i = 0, k = saved_IS; i < sim_emax; i++, k++) { | |
| if (cpu_ex (&sim_eval[i], k, &cpu_unit, 0) != SCPE_OK) | |
| break; | |
| } | |
| fprint_sym (sim_deb, saved_IS, sim_eval, &cpu_unit, SWMASK('M')); | |
| fprintf (sim_deb, "\n" ); | |
| } | |
| switch (op) { /* case on opcode */ | |
| /* Move/load character instructions A check B check | |
| MCW copy A to B, preserving B WM, here fetch | |
| until either A or B WM | |
| LCA copy A to B, overwriting B WM, here fetch | |
| until A WM | |
| Instruction lengths: | |
| 1 chained A and B | |
| 2,3 invalid A-address | |
| 4 chained B address | |
| 5,6 invalid B-address | |
| 7 normal | |
| 8+ normal + modifier | |
| */ | |
| case OP_MCW: /* move char */ | |
| if ((ilnt >= 4) && (ioind == BCD_PERCNT)) { /* I/O form? */ | |
| reason = iodisp (dev, unit, MD_NORM, D); /* dispatch I/O */ | |
| break; | |
| } | |
| if (ADDR_ERR (AS)) { /* check A addr */ | |
| reason = STOP_INVA; | |
| break; | |
| } | |
| do { | |
| wm = M[AS] | M[BS]; | |
| M[BS] = (M[BS] & WM) | (M[AS] & CHAR); /* move char */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| } while ((wm & WM) == 0); /* stop on A,B WM */ | |
| break; | |
| case OP_LCA: /* load char */ | |
| if ((ilnt >= 4) && (ioind == BCD_PERCNT)) { /* I/O form? */ | |
| reason = iodisp (dev, unit, MD_WM, D); | |
| break; | |
| } | |
| if (ADDR_ERR (AS)) { /* check A addr */ | |
| reason = STOP_INVA; | |
| break; | |
| } | |
| do { | |
| wm = M[BS] = M[AS]; /* move char + wmark */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| } while ((wm & WM) == 0); /* stop on A WM */ | |
| break; | |
| /* Other move instructions A check B check | |
| MCM copy A to B, preserving B WM, fetch fetch | |
| until record or group mark | |
| MCS copy A to B, clearing B WM, until A WM; fetch fetch | |
| reverse scan and suppress leading zeroes | |
| MN copy A char digit to B char digit, fetch fetch | |
| preserving B zone and WM | |
| MZ copy A char zone to B char zone, fetch fetch | |
| preserving B digit and WM | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address | |
| 4 self (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 normal | |
| 8+ normal + ignored modifier | |
| */ | |
| case OP_MCM: /* move to rec/group */ | |
| do { | |
| t = M[AS]; | |
| M[BS] = (M[BS] & WM) | (M[AS] & CHAR); /* move char */ | |
| PP (AS); /* incr pointers */ | |
| PP (BS); | |
| } while (((t & CHAR) != BCD_RECMRK) && (t != (BCD_GRPMRK + WM))); | |
| break; | |
| case OP_MCS: /* move suppress zero */ | |
| bsave = BS; /* save B start */ | |
| qzero = 1; /* set suppress */ | |
| do { | |
| wm = M[AS]; | |
| M[BS] = M[AS] & ((BS != bsave)? CHAR: DIGIT);/* copy char */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| } while ((wm & WM) == 0); /* stop on A WM */ | |
| if (reason) /* addr err? stop */ | |
| break; | |
| do { | |
| PP (BS); /* adv B */ | |
| t = M[BS]; /* get B, cant be WM */ | |
| if ((t == BCD_ZERO) || (t == BCD_COMMA)) { | |
| if (qzero) | |
| M[BS] = 0; | |
| } | |
| else if ((t == BCD_BLANK) || (t == BCD_MINUS)) ; | |
| else if (((t == BCD_DECIMAL) && (cpu_unit.flags & EPE)) || | |
| (t <= BCD_NINE)) | |
| qzero = 0; | |
| else qzero = 1; | |
| } while (BS < bsave); | |
| PP (BS); /* BS end is B+1 */ | |
| break; | |
| case OP_MN: /* move numeric */ | |
| M[BS] = (M[BS] & ~DIGIT) | (M[AS] & DIGIT); /* move digit */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| break; | |
| case OP_MZ: /* move zone */ | |
| M[BS] = (M[BS] & ~ZONE) | (M[AS] & ZONE); /* move high bits */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| break; | |
| /* Branch instruction A check B check | |
| Instruction lengths: | |
| 1 branch if B char equals d, chained if branch here | |
| 2,3 invalid B-address if branch here | |
| 4 unconditional branch if branch | |
| 5 branch if indicator[d] is set if branch | |
| 6 invalid B-address if branch here | |
| 7 branch if B char equals d, if branch here | |
| d is last character of B-address | |
| 8 branch if B char equals d if branch here | |
| */ | |
| case OP_B: /* branch */ | |
| if (ilnt == 4) { /* uncond branch? */ | |
| BRANCH; | |
| } | |
| else if (ilnt == 5) { /* branch on ind? */ | |
| if (ind[D]) { /* test indicator */ | |
| BRANCH; | |
| } | |
| if (ind_table[D]) /* reset if needed */ | |
| ind[D] = 0; | |
| } | |
| else { /* branch char eq */ | |
| if (ADDR_ERR (BS)) { /* validate B addr */ | |
| reason = STOP_INVB; | |
| break; | |
| } | |
| if ((M[BS] & CHAR) == D) { /* char equal? */ | |
| BRANCH; | |
| } | |
| else { | |
| MM (BS); | |
| } | |
| } | |
| break; | |
| /* Other branch instructions A check B check | |
| BWZ branch if (d<0>: B char WM) if branch fetch | |
| (d<1>: B char zone = d zone) | |
| BBE branch if B char & d non-zero if branch fetch | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address and B-address | |
| 4 self (B-address = A-address, d = last character of A-address) | |
| 5,6 invalid B-address | |
| 7 normal, d = last character of B-address | |
| 8+ normal | |
| */ | |
| case OP_BWZ: /* branch wm or zone */ | |
| if (((D & 1) && (M[BS] & WM)) || /* d1? test wm */ | |
| ((D & 2) && ((M[BS] & ZONE) == (D & ZONE)))) { /* d2? test zone */ | |
| BRANCH; | |
| } | |
| else { /* decr pointer */ | |
| MM (BS); | |
| } | |
| break; | |
| case OP_BBE: /* branch if bit eq */ | |
| if (M[BS] & D & CHAR) { /* any bits set? */ | |
| BRANCH; | |
| } | |
| else { /* decr pointer */ | |
| MM (BS); | |
| } | |
| break; | |
| /* Arithmetic instructions A check B check | |
| ZA move A to B, normalizing A sign, fetch fetch | |
| preserving B WM, until B WM | |
| ZS move A to B, complementing A sign, fetch fetch | |
| preserving B WM, until B WM | |
| A add A to B fetch fetch | |
| S subtract A from B fetch fetch | |
| C compare A to B fetch fetch | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address | |
| 4 self (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 normal | |
| 8+ normal + ignored modifier | |
| Despite their names, ZA and ZS are not arithmetic instructions, but copies | |
| with zone stripping. The adder is not used, so BCD conversions do not occur. | |
| */ | |
| case OP_ZA: case OP_ZS: /* zero and add/sub */ | |
| a = i = 0; /* clear flags */ | |
| do { | |
| if (a & WM) /* A word mark? */ | |
| wm = M[BS] = (M[BS] & WM) | BCD_ZERO; | |
| else { | |
| a = M[AS]; /* get A char */ | |
| t = a & DIGIT; /* zap zone bits */ | |
| wm = M[BS] = (M[BS] & WM) | t; /* store digit */ | |
| MM (AS); | |
| } | |
| if (i == 0) | |
| i = M[BS] = M[BS] | | |
| ((((a & ZONE) == BBIT) ^ (op == OP_ZS))? BBIT: ZONE); | |
| MM (BS); | |
| } while ((wm & WM) == 0); /* stop on B WM */ | |
| break; | |
| case OP_A: case OP_S: /* add/sub */ | |
| bsave = BS; /* save sign pos */ | |
| a = M[AS]; /* get A digit/sign */ | |
| b = M[BS]; /* get B digit/sign */ | |
| MM (AS); | |
| qsign = ((a & ZONE) == BBIT) ^ ((b & ZONE) == BBIT) ^ (op == OP_S); | |
| t = bcd_to_bin[a & DIGIT]; /* get A binary */ | |
| t = bcd_to_bin[b & DIGIT] + (qsign? 10 - t: t); /* sum A + B */ | |
| carry = (t >= 10); /* get carry */ | |
| b = (b & ~DIGIT) | sum_table[t]; /* get result */ | |
| if (qsign && ((b & BBIT) == 0)) /* normalize sign */ | |
| b = b | ZONE; | |
| M[BS] = b; /* store result */ | |
| MM (BS); | |
| if (b & WM) { /* b wm? done */ | |
| if (qsign && (carry == 0)) /* compl, no carry? */ | |
| M[bsave] = WM + ((b & ZONE) ^ ABIT) + sum_table[10 - t]; | |
| break; | |
| } | |
| do { | |
| if (a & WM) /* A WM? char = 0 */ | |
| a = WM; | |
| else { | |
| a = M[AS]; /* else get A */ | |
| MM (AS); | |
| } | |
| b = M[BS]; /* get B */ | |
| t = bcd_to_bin[a & DIGIT]; /* get A binary */ | |
| t = bcd_to_bin[b & DIGIT] + (qsign? 9 - t: t) + carry; | |
| carry = (t >= 10); /* get carry */ | |
| if ((b & WM) && (qsign == 0)) { /* last, no recomp? */ | |
| M[BS] = WM + sum_table[t] + /* zone add */ | |
| (((a & ZONE) + b + (carry? ABIT: 0)) & ZONE); | |
| ind[IN_OVF] = carry; /* ovflo if carry */ | |
| } | |
| else M[BS] = (b & WM) + sum_table[t]; /* normal add */ | |
| MM (BS); | |
| } while ((b & WM) == 0); /* stop on B WM */ | |
| if (reason) /* address err? */ | |
| break; | |
| if (qsign && (carry == 0)) { /* recompl, no carry? */ | |
| M[bsave] = M[bsave] ^ ABIT; /* XOR sign */ | |
| for (carry = 1; bsave != BS; --bsave) { /* rescan */ | |
| t = 9 - bcd_to_bin[M[bsave] & DIGIT] + carry; | |
| carry = (t >= 10); | |
| M[bsave] = (M[bsave] & ~DIGIT) | sum_table[t]; | |
| } | |
| } | |
| break; | |
| case OP_C: /* compare */ | |
| if (ilnt != 1) { /* if not chained */ | |
| ind[IN_EQU] = 1; /* clear indicators */ | |
| ind[IN_UNQ] = ind[IN_HGH] = ind[IN_LOW] = 0; | |
| } | |
| do { | |
| a = M[AS]; /* get characters */ | |
| b = M[BS]; | |
| wm = a | b; /* get word marks */ | |
| if ((a & CHAR) != (b & CHAR)) { /* unequal? */ | |
| ind[IN_EQU] = 0; /* set indicators */ | |
| ind[IN_UNQ] = 1; | |
| ind[IN_HGH] = col_table[b & CHAR] > col_table [a & CHAR]; | |
| ind[IN_LOW] = ind[IN_HGH] ^ 1; | |
| } | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| } while ((wm & WM) == 0); /* stop on A, B WM */ | |
| if ((a & WM) && !(b & WM)) { /* short A field? */ | |
| ind[IN_EQU] = ind[IN_LOW] = 0; | |
| ind[IN_UNQ] = ind[IN_HGH] = 1; | |
| } | |
| if (!(cpu_unit.flags & HLE)) /* no HLE? */ | |
| ind[IN_EQU] = ind[IN_LOW] = ind[IN_HGH] = 0; | |
| break; | |
| /* I/O instructions A check B check | |
| R read a card if branch | |
| W write to line printer if branch | |
| WR write and read if branch | |
| P punch a card if branch | |
| RP read and punch if branch | |
| WP : write and punch if branch | |
| WRP write read and punch if branch | |
| RF read feed (nop) | |
| PF punch feed (nop) | |
| SS select stacker if branch | |
| CC carriage control if branch | |
| Instruction lengths: | |
| 1 normal | |
| 2,3 normal, with modifier | |
| 4 branch; modifier, if any, is last character of branch address | |
| 5 branch + modifier | |
| 6+ normal, with modifier | |
| */ | |
| case OP_R: /* read */ | |
| if ((reason = iomod (ilnt, D, r_mod))) /* valid modifier? */ | |
| break; | |
| reason = read_card (ilnt, D); /* read card */ | |
| BS = CDR_BUF + CDR_WIDTH; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| break; | |
| case OP_W: /* write */ | |
| if ((reason = iomod (ilnt, D, w_mod))) /* valid modifier? */ | |
| break; | |
| reason = write_line (ilnt, D); /* print line */ | |
| BS = LPT_BUF + LPT_WIDTH; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| break; | |
| case OP_P: /* punch */ | |
| if ((reason = iomod (ilnt, D, p_mod))) /* valid modifier? */ | |
| break; | |
| reason = punch_card (ilnt, D); /* punch card */ | |
| BS = CDP_BUF + CDP_WIDTH; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| break; | |
| case OP_WR: /* write and read */ | |
| if ((reason = iomod (ilnt, D, w_mod))) /* valid modifier? */ | |
| break; | |
| reason = write_line (ilnt, D); /* print line */ | |
| r1 = read_card (ilnt, D); /* read card */ | |
| BS = CDR_BUF + CDR_WIDTH; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| if (reason == SCPE_OK) /* merge errors */ | |
| reason = r1; | |
| break; | |
| case OP_WP: /* write and punch */ | |
| if ((reason = iomod (ilnt, D, w_mod))) /* valid modifier? */ | |
| break; | |
| reason = write_line (ilnt, D); /* print line */ | |
| r1 = punch_card (ilnt, D); /* punch card */ | |
| BS = CDP_BUF + CDP_WIDTH; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| if (reason == SCPE_OK) /* merge errors */ | |
| reason = r1; | |
| break; | |
| case OP_RP: /* read and punch */ | |
| if ((reason = iomod (ilnt, D, NULL))) /* valid modifier? */ | |
| break; | |
| reason = read_card (ilnt, D); /* read card */ | |
| r1 = punch_card (ilnt, D); /* punch card */ | |
| BS = CDP_BUF + CDP_WIDTH; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| if (reason == SCPE_OK) /* merge errors */ | |
| reason = r1; | |
| break; | |
| case OP_WRP: /* write, read, punch */ | |
| if ((reason = iomod (ilnt, D, w_mod))) /* valid modifier? */ | |
| break; | |
| reason = write_line (ilnt, D); /* print line */ | |
| r1 = read_card (ilnt, D); /* read card */ | |
| r2 = punch_card (ilnt, D); /* punch card */ | |
| BS = CDP_BUF + CDP_WIDTH; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| if (reason == SCPE_OK) /* merge errors */ | |
| reason = (r1 == SCPE_OK)? r2: r1; | |
| break; | |
| case OP_SS: /* select stacker */ | |
| if ((reason = iomod (ilnt, D, ss_mod))) /* valid modifier? */ | |
| break; | |
| if ((reason = select_stack (D))) /* sel stack, error? */ | |
| break; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| break; | |
| case OP_CC: /* carriage control */ | |
| if ((reason = carriage_control (D))) /* car ctrl, error? */ | |
| break; | |
| if ((ilnt == 4) || (ilnt == 5)) { /* check for branch */ | |
| BRANCH; | |
| } | |
| break; | |
| /* MTF - magtape functions - must be at least 4 characters | |
| Instruction lengths: | |
| 1-3 invalid I/O address | |
| 4 normal, d-character is unit | |
| 5 normal | |
| 6+ normal, d-character is last character | |
| */ | |
| case OP_MTF: /* magtape function */ | |
| if (ilnt < 4) /* too short? */ | |
| reason = STOP_INVL; | |
| else if (ioind != BCD_PERCNT) /* valid dev addr? */ | |
| reason = STOP_INVA; | |
| else if ((reason = iomod (ilnt, D, mtf_mod))) /* valid modifier? */ | |
| break; | |
| if (dev == IO_MT) /* BCD? */ | |
| reason = mt_func (unit, 0, D); | |
| else if (dev == IO_MTB) /* binary? */ | |
| reason = mt_func (unit, MD_BIN, D); | |
| else reason = STOP_INVA; /* wrong device */ | |
| break; /* can't branch */ | |
| case OP_RF: case OP_PF: /* read, punch feed */ | |
| break; /* nop's */ | |
| /* Move character and edit | |
| Control flags | |
| qsign sign of A field (0 = +, 1 = minus) | |
| qawm A field WM seen and processed | |
| qzero zero suppression enabled | |
| qbody in body (copying A field characters) | |
| qdollar EPE only; $ seen in body | |
| qaster EPE only; * seen in body | |
| qdecimal EPE only; . seen on first rescan | |
| MCE operates in one to three scans, the first of which has three phases | |
| 1 right to left qbody = 0, qawm = 0 => right status | |
| qbody = 1, qawm = 0 => body | |
| qbody = 0, qawm = 1 => left status | |
| 2 left to right | |
| 3 right to left, extended print end only | |
| The first A field character is masked to its digit part, all others | |
| are copied intact | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address | |
| 4 self (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 normal | |
| 8+ normal + ignored modifier | |
| */ | |
| case OP_MCE: /* edit */ | |
| a = M[AS]; /* get A char */ | |
| b = M[BS]; /* get B char */ | |
| t = a & DIGIT; /* get A digit */ | |
| MM (AS); | |
| qsign = ((a & ZONE) == BBIT); /* get A field sign */ | |
| qawm = qzero = qbody = 0; /* clear other flags */ | |
| qdollar = qaster = qdecimal = 0; /* clear EPE flags */ | |
| /* Edit pass 1 - from right to left, under B field control | |
| * in status or !epe, skip B; else, set qaster, repl with A | |
| $ in status or !epe, skip B; else, set qdollar, repl with A | |
| 0 in right status or body, if !qzero, set A WM; set qzero, repl with A | |
| else, if !qzero, skip B; else, if (!B WM) set B WM | |
| blank in right status or body, repl with A; else, skip B | |
| C,R,- in status, blank B; else, skip B | |
| , in status, blank B, else, skip B | |
| & blank B | |
| */ | |
| do { | |
| b = M[BS]; /* get B char */ | |
| M[BS] = M[BS] & ~WM; /* clr WM */ | |
| switch (b & CHAR) { /* case on B char */ | |
| case BCD_ASTER: /* * */ | |
| if (!qbody || qdollar || !(cpu_unit.flags & EPE)) | |
| break; | |
| qaster = 1; /* flag */ | |
| goto A_CYCLE; /* take A cycle */ | |
| case BCD_DOLLAR: /* $ */ | |
| if (!qbody || qaster || !(cpu_unit.flags & EPE)) | |
| break; | |
| qdollar = 1; /* flag */ | |
| goto A_CYCLE; /* take A cycle */ | |
| case BCD_ZERO: /* 0 */ | |
| if (qawm) { /* left status? */ | |
| if (!qzero) /* first? set WM */ | |
| M[BS] = M[BS] | WM; | |
| qzero = 1; /* flag suppress */ | |
| break; | |
| } | |
| if (!qzero) /* body, first? WM */ | |
| t = t | WM; | |
| qzero = 1; /* flag suppress */ | |
| goto A_CYCLE; /* take A cycle */ | |
| case BCD_BLANK: /* blank */ | |
| if (qawm) /* left status? */ | |
| break; | |
| A_CYCLE: | |
| M[BS] = t; /* copy char */ | |
| if (a & WM) { /* end of A field? */ | |
| qbody = 0; /* end body */ | |
| qawm = 1; /* start left status */ | |
| } | |
| else { | |
| qbody = 1; /* in body */ | |
| a = M[AS]; /* next A */ | |
| MM (AS); | |
| t = a & CHAR; /* use A char */ | |
| } | |
| break; | |
| case BCD_C: case BCD_R: case BCD_MINUS: /* C, R, - */ | |
| if (!qsign && !qbody) /* + & status? blank */ | |
| M[BS] = BCD_BLANK; | |
| break; | |
| case BCD_COMMA: /* , */ | |
| if (!qbody) /* status? blank */ | |
| M[BS] = BCD_BLANK; | |
| break; | |
| case BCD_AMPER: /* & */ | |
| M[BS] = BCD_BLANK; /* blank */ | |
| break; | |
| } /* end switch */ | |
| MM (BS); /* decr B pointer */ | |
| } while ((b & WM) == 0); /* stop on B WM */ | |
| if (reason) /* address err? */ | |
| break; | |
| if (!qzero) /* rescan? */ | |
| break; | |
| /* Edit pass 2 - from left to right, suppressing zeroes */ | |
| do { | |
| b = M[++BS]; /* get B char */ | |
| switch (b & CHAR) { /* case on B char */ | |
| case BCD_ONE: case BCD_TWO: case BCD_THREE: | |
| case BCD_FOUR: case BCD_FIVE: case BCD_SIX: | |
| case BCD_SEVEN: case BCD_EIGHT: case BCD_NINE: | |
| qzero = 0; /* turn off supr */ | |
| break; | |
| case BCD_ZERO: case BCD_COMMA: /* 0 or , */ | |
| if (qzero && !qdecimal) /* if supr, blank */ | |
| M[BS] = qaster? BCD_ASTER: BCD_BLANK; | |
| break; | |
| case BCD_BLANK: /* blank */ | |
| if (qaster) /* if EPE *, repl */ | |
| M[BS] = BCD_ASTER; | |
| break; | |
| case BCD_DECIMAL: /* . */ | |
| if (qzero && (cpu_unit.flags & EPE)) /* flag for EPE */ | |
| qdecimal = 1; | |
| break; | |
| case BCD_PERCNT: case BCD_WM: case BCD_BS: | |
| case BCD_TS: case BCD_MINUS: | |
| break; /* ignore */ | |
| default: /* other */ | |
| qzero = 1; /* restart supr */ | |
| break; | |
| } /* end case */ | |
| } while ((b & WM) == 0); | |
| M[BS] = M[BS] & ~WM; /* clear B WM */ | |
| if (!qdollar && !(qdecimal && qzero)) { /* rescan again? */ | |
| BS++; /* BS = addr WM + 1 */ | |
| break; | |
| } | |
| if (qdecimal && qzero) /* no digits? clr $ */ | |
| qdollar = 0; | |
| /* Edit pass 3 (extended print only) - from right to left */ | |
| for (;; ) { /* until chars */ | |
| b = M[BS]; /* get B char */ | |
| if ((b == BCD_BLANK) && qdollar) { /* blank & flt $? */ | |
| M[BS] = BCD_DOLLAR; /* insert $ */ | |
| break; /* exit for */ | |
| } | |
| if (b == BCD_DECIMAL) { /* decimal? */ | |
| M[BS] = qaster? BCD_ASTER: BCD_BLANK; | |
| break; /* exit for */ | |
| } | |
| if ((b == BCD_ZERO) && !qdollar) /* 0 & ~flt $ */ | |
| M[BS] = qaster? BCD_ASTER: BCD_BLANK; | |
| BS--; | |
| } /* end for */ | |
| break; /* done at last! */ | |
| /* Multiply. Comments from the PDP-10 based simulator by Len Fehskens. | |
| Multiply, with variable length operands, is necessarily done the same | |
| way you do it with paper and pencil, except that partial products are | |
| added into the incomplete final product as they are computed, rather | |
| than at the end. The 1401 multiplier format allows the product to | |
| be developed in place, without scratch storage. | |
| The A field contains the multiplicand, length LD. The B field must be | |
| LD + 1 + length of multiplier. Locate the low order multiplier digit, | |
| and at the same time zero out the product field. Then compute the sign | |
| of the result. | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address | |
| 4 self (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 normal | |
| 8+ normal + ignored modifier | |
| */ | |
| case OP_MUL: | |
| asave = AS; /* save AS, BS */ | |
| bsave = lowprd = BS; | |
| do { | |
| a = M[AS]; /* get mpcd char */ | |
| M[BS] = BCD_ZERO; /* zero prod */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| } while ((a & WM) == 0); /* until A WM */ | |
| if (reason) /* address err? */ | |
| break; | |
| M[BS] = BCD_ZERO; /* zero hi prod */ | |
| MM (BS); /* addr low mpyr */ | |
| sign = ((M[asave] & ZONE) == BBIT) ^ ((M[BS] & ZONE) == BBIT); | |
| /* Outer loop on multiplier (BS) and product digits (ps), | |
| inner loop on multiplicand digits (AS). | |
| AS and ps cannot produce an address error. | |
| */ | |
| do { | |
| ps = bsave; /* ptr to prod */ | |
| AS = asave; /* ptr to mpcd */ | |
| carry = 0; /* init carry */ | |
| b = M[BS]; /* get mpyr char */ | |
| do { | |
| a = M[AS]; /* get mpcd char */ | |
| t = (bcd_to_bin[a & DIGIT] * /* mpyr * mpcd */ | |
| bcd_to_bin[b & DIGIT]) + /* + c + partial prod */ | |
| carry + bcd_to_bin[M[ps] & DIGIT]; | |
| carry = cry_table[t]; | |
| M[ps] = (M[ps] & WM) | sum_table[t]; | |
| MM (AS); | |
| ps--; | |
| } while ((a & WM) == 0); /* until mpcd done */ | |
| M[BS] = (M[BS] & WM) | BCD_ZERO; /* zero mpyr just used */ | |
| t = bcd_to_bin[M[ps] & DIGIT] + carry; /* add carry to prod */ | |
| M[ps] = (M[ps] & WM) | sum_table[t]; /* store */ | |
| bsave--; /* adv prod ptr */ | |
| MM (BS); /* adv mpyr ptr */ | |
| } while ((b & WM) == 0); /* until mpyr done */ | |
| M[lowprd] = M[lowprd] | ZONE; /* assume + */ | |
| if (sign) /* if minus, B only */ | |
| M[lowprd] = M[lowprd] & ~ABIT; | |
| break; | |
| /* Divide. Comments from the PDP-10 based simulator by Len Fehskens. | |
| Divide is done, like multiply, pretty much the same way you do it with | |
| pencil and paper; successive subtraction of the divisor from a substring | |
| of the dividend while counting up the corresponding quotient digit. | |
| Let LS be the length of the divisor, LD the length of the dividend: | |
| - AS points to the low order divisor digit. | |
| - BS points to the high order dividend digit. | |
| - The low order dividend digit is identified by sign (zone) bits. | |
| - To the left of the dividend is a (zero) field of length LS + 1. | |
| So the quotient starts as BS - LS - 1. | |
| The divide process starts with a subdividend that begins at BS - LS | |
| and ends at BS. (Note that the subdividend is one digit wider than | |
| the divisor, to allow for borrows during the divide process.) This | |
| means that non-zero digits in the "zero" field to the left of the | |
| dividend CAN affect the divide. | |
| Start by computing the length of the divisor and testing for divide | |
| by zero. | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address | |
| 4 self (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 normal | |
| 8+ normal + ignored modifier | |
| */ | |
| case OP_DIV: | |
| asave = AS; | |
| t = 0; /* assume all 0's */ | |
| do { /* scan divisor */ | |
| a = M[AS]; /* get dvr char */ | |
| if ((bcd_to_bin[a & DIGIT]) != 0) /* mark non-zero */ | |
| t = 1; | |
| MM (AS); | |
| } | |
| while ((a & WM) == 0); | |
| if (reason) /* address err? */ | |
| break; | |
| if (t == 0) { /* div by zero? */ | |
| ind[IN_OVF] = 1; /* set ovf indic */ | |
| qs = bsave = BS; /* quo, dividend */ | |
| do { | |
| b = M[bsave]; /* find end divd */ | |
| PP (bsave); /* marked by zone */ | |
| } while ((b & ZONE) == 0); | |
| if (reason) /* address err? */ | |
| break; | |
| if (ADDR_ERR (qs)) { /* address err? */ | |
| reason = STOP_WRAP; /* address wrap? */ | |
| break; | |
| } | |
| div_sign (M[asave], b, qs - 1, bsave - 1); /* set signs */ | |
| BS = (BS - 2) - (asave - (AS + 1)); /* final bs */ | |
| break; | |
| } | |
| bsave = BS; /* end subdivd */ | |
| qs = BS - (asave - AS) - 1; /* quo start */ | |
| /* Divide loop - done with subroutines to keep the code clean. | |
| In the loop, | |
| asave = low order divisor (constant) | |
| bsave = low order subdividend (increments) | |
| qs = current quotient digit (increments) | |
| */ | |
| do { | |
| quo = 0; /* clear quo digit */ | |
| if (ADDR_ERR (qs) || ADDR_ERR (bsave)) { | |
| reason = STOP_WRAP; /* address wrap? */ | |
| break; | |
| } | |
| b = M[bsave]; /* save low divd */ | |
| do { | |
| t = div_sub (asave, bsave); /* subtract */ | |
| quo++; /* incr quo digit */ | |
| } while (t == 0); /* until borrow */ | |
| div_add (asave, bsave); /* restore */ | |
| quo--; | |
| if (quo > 9) /* overflow? */ | |
| ind[IN_OVF] = 1; /* set ovf indic */ | |
| M[qs] = (M[qs] & WM) | sum_table[quo]; /* store quo digit */ | |
| bsave++; /* adv divd, quo */ | |
| qs++; | |
| } while ((b & ZONE) == 0); /* until B sign */ | |
| if (reason) /* address err? */ | |
| break; | |
| /* At this point, | |
| AS = high order divisor - 1 | |
| asave = unit position of divisor | |
| b = unit character of dividend | |
| bsave = unit position of remainder + 1 | |
| qs = unit position of quotient + 1 | |
| */ | |
| div_sign (M[asave], b, qs - 1, bsave - 1); /* set signs */ | |
| BS = qs - 2; /* BS = quo 10's pos */ | |
| break; | |
| /* Word mark instructions A check B check | |
| SWM set WM on A char and B char fetch fetch | |
| CWM clear WM on A char and B char fetch fetch | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address | |
| 4 one operand (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 two operands (SWM cannot be longer than 7) | |
| 8+ two operands + ignored modifier | |
| */ | |
| case OP_SWM: /* set word mark */ | |
| M[BS] = M[BS] | WM; /* set A field mark */ | |
| M[AS] = M[AS] | WM; /* set B field mark */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| break; | |
| case OP_CWM: /* clear word mark */ | |
| M[BS] = M[BS] & ~WM; /* clear A field mark */ | |
| M[AS] = M[AS] & ~WM; /* clear B field mark */ | |
| MM (AS); /* decr pointers */ | |
| MM (BS); | |
| break; | |
| /* Clear storage instruction A check B check | |
| CS clear from B down to nearest hundreds if branch fetch | |
| address | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address and B-address | |
| 4 one operand (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 branch | |
| 8+ one operand, branch ignored | |
| Note that clear storage and branch does not overwrite the B register, | |
| unlike all other branches | |
| */ | |
| case OP_CS: /* clear storage */ | |
| t = (BS / 100) * 100; /* lower bound */ | |
| while (BS >= t) /* clear region */ | |
| M[BS--] = 0; | |
| if (BS < 0) /* wrap if needed */ | |
| BS = BS + MEMSIZE; | |
| if (ilnt == 7) { /* branch variant? */ | |
| BRANCH_CS; /* special branch */ | |
| } | |
| break; | |
| /* Modify address instruction A check B check | |
| MA add A addr and B addr, store at B addr fetch fetch | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address and B-address | |
| 4 self (B-address = A-address) | |
| 5,6 invalid B-address | |
| 7 normal | |
| 8+ normal + ignored modifier | |
| */ | |
| case OP_MA: /* modify address */ | |
| a = one_table[M[AS] & CHAR]; MM (AS); /* get A address */ | |
| a = a + ten_table[M[AS] & CHAR]; MM (AS); | |
| a = a + hun_table[M[AS] & CHAR]; MM (AS); | |
| b = one_table[M[BS] & CHAR]; MM (BS); /* get B address */ | |
| b = b + ten_table[M[BS] & CHAR]; MM (BS); | |
| b = b + hun_table[M[BS] & CHAR]; MM (BS); | |
| t = ((a + b) & INDEXMASK) % MAXMEMSIZE; /* compute sum */ | |
| M[BS + 3] = (M[BS + 3] & WM) | store_addr_u (t); | |
| M[BS + 2] = (M[BS + 2] & (WM + ZONE)) | store_addr_t (t); | |
| M[BS + 1] = (M[BS + 1] & WM) | store_addr_h (t); | |
| if (((a % 4000) + (b % 4000)) >= 4000) /* carry? */ | |
| BS = BS + 2; | |
| break; | |
| /* Store address instructions A-check B-check | |
| SAR store A* at A addr fetch | |
| SBR store B* at A addr fetch | |
| Instruction lengths: | |
| 1 chained | |
| 2,3 invalid A-address | |
| 4 normal | |
| 5+ B-address overwritten from instruction; | |
| invalid address ignored | |
| */ | |
| case OP_SAR: case OP_SBR: /* store A, B reg */ | |
| M[AS] = (M[AS] & WM) | store_addr_u (BS); | |
| MM (AS); | |
| M[AS] = (M[AS] & WM) | store_addr_t (BS); | |
| MM (AS); | |
| M[AS] = (M[AS] & WM) | store_addr_h (BS); | |
| MM (AS); | |
| break; | |
| /* NOP - no validity checking, all instructions length ok */ | |
| case OP_NOP: /* nop */ | |
| break; | |
| /* HALT - unless length = 4 (branch), no validity checking; all lengths ok */ | |
| case OP_H: /* halt */ | |
| if (ilnt == 4) /* set pending branch */ | |
| hb_pend = 1; | |
| reason = STOP_HALT; /* stop simulator */ | |
| saved_IS = IS; /* commit instruction */ | |
| break; | |
| default: | |
| reason = STOP_NXI; /* unimplemented */ | |
| break; | |
| } /* end switch */ | |
| } /* end while */ | |
| /* Simulation halted */ | |
| as_err = ADDR_ERR (AS); /* get addr err flags */ | |
| bs_err = ADDR_ERR (BS); | |
| AS = AS & ADDRMASK; /* clean addresses */ | |
| BS = BS & ADDRMASK; | |
| pcq_r->qptr = pcq_p; /* update pc q ptr */ | |
| return reason; | |
| } /* end sim_instr */ | |
| /* store addr_x - convert address to BCD character in x position | |
| Inputs: | |
| addr = address to convert | |
| Outputs: | |
| char = converted address character | |
| */ | |
| int32 store_addr_h (int32 addr) | |
| { | |
| int32 thous; | |
| thous = (addr / 1000) & 03; | |
| return bin_to_bcd[(addr % 1000) / 100] | (thous << V_ZONE); | |
| } | |
| int32 store_addr_t (int32 addr) | |
| { | |
| return bin_to_bcd[(addr % 100) / 10]; | |
| } | |
| int32 store_addr_u (int32 addr) | |
| { | |
| int32 thous; | |
| thous = (addr / 1000) & 014; | |
| return bin_to_bcd[addr % 10] | (thous << (V_ZONE - 2)); | |
| } | |
| /* div_add - add string for divide */ | |
| int32 div_add (int32 ap, int32 bp) | |
| { | |
| int32 a, b, c, r; | |
| c = 0; /* init carry */ | |
| do { | |
| a = M[ap]; /* get operands */ | |
| b = M[bp]; | |
| r = bcd_to_bin[b & DIGIT] + /* sum digits + c */ | |
| bcd_to_bin[a & DIGIT] + c; | |
| c = (r >= 10); /* set carry out */ | |
| M[bp] = (M[bp] & WM) | sum_table[r]; /* store result */ | |
| ap--; | |
| bp--; | |
| } while ((a & WM) == 0); | |
| return c; | |
| } | |
| /* div_sub - substract string for divide */ | |
| int32 div_sub (int32 ap, int32 bp) | |
| { | |
| int32 a, b, c, r; | |
| c = 0; /* init borrow */ | |
| do { | |
| a = M[ap]; /* get operands */ | |
| b = M[bp]; | |
| r = bcd_to_bin[b & DIGIT] - /* a - b - borrow */ | |
| bcd_to_bin[a & DIGIT] - c; | |
| c = (r < 0); /* set borrow out */ | |
| M[bp] = (M[bp] & WM) | sum_table[r + 10]; /* store result */ | |
| ap--; | |
| bp--; | |
| } while ((a & WM) == 0); | |
| b = M[bp]; /* borrow position */ | |
| if (bcd_to_bin[b & DIGIT] != 0) { /* non-zero? */ | |
| r = bcd_to_bin[b & DIGIT] - c; /* subtract borrow */ | |
| M[bp] = (M[bp] & WM) | sum_table[r]; /* store result */ | |
| return 0; /* subtract worked */ | |
| } | |
| return c; /* return borrow */ | |
| } | |
| /* div_sign - set signs for divide */ | |
| void div_sign (int32 dvrc, int32 dvdc, int32 qp, int32 rp) | |
| { | |
| int32 sign = dvrc & ZONE; /* divisor sign */ | |
| M[rp] = M[rp] | ZONE; /* assume rem pos */ | |
| if (sign == BBIT) /* if dvr -, rem - */ | |
| M[rp] = M[rp] & ~ABIT; | |
| M[qp] = M[qp] | ZONE; /* assume quo + */ | |
| if (((dvdc & ZONE) == BBIT) ^ (sign == BBIT)) /* dvr,dvd diff? */ | |
| M[qp] = M[qp] & ~ABIT; /* make quo - */ | |
| return; | |
| } | |
| /* iomod - check on I/O modifiers | |
| Inputs: | |
| ilnt = instruction length | |
| mod = modifier character | |
| tptr = pointer to table of modifiers, end is -1 | |
| Output: | |
| status = SCPE_OK if ok, STOP_INVM if invalid | |
| */ | |
| t_stat iomod (int32 ilnt, int32 mod, const int32 *tptr) | |
| { | |
| if ((ilnt != 2) && (ilnt != 5) && (ilnt < 8)) | |
| return SCPE_OK; | |
| if (tptr == NULL) | |
| return STOP_INVM; | |
| do { | |
| if (mod == *tptr++) | |
| return SCPE_OK; | |
| } while (*tptr >= 0); | |
| return STOP_INVM; | |
| } | |
| /* iodisp - dispatch load or move to I/O routine | |
| Inputs: | |
| dev = device number | |
| unit = unit number | |
| flag = move (MD_NORM) vs load (MD_WM) | |
| mod = modifier | |
| */ | |
| t_stat iodisp (int32 dev, int32 unit, int32 flag, int32 mod) | |
| { | |
| if (dev == IO_INQ) /* inq terminal? */ | |
| return inq_io (flag, mod); | |
| if (dev == IO_DP) /* disk pack? */ | |
| return dp_io (unit, flag, mod); | |
| if (dev == IO_MT) /* magtape? */ | |
| return mt_io (unit, flag, mod); | |
| if (dev == IO_MTB) /* binary magtape? */ | |
| return mt_io (unit, flag | MD_BIN, mod); | |
| return STOP_NXD; /* not implemented */ | |
| } | |
| /* Reset routine */ | |
| t_stat cpu_reset (DEVICE *dptr) | |
| { | |
| int32 i; | |
| for (i = 0; i < 64; i++) { /* clr indicators */ | |
| if ((i < IN_SSB) || (i > IN_SSG)) /* except SSB-SSG */ | |
| ind[i] = 0; | |
| } | |
| ind[IN_UNC] = 1; /* ind[0] always on */ | |
| AS = 0; /* clear AS */ | |
| BS = 0; /* clear BS */ | |
| as_err = 1; | |
| bs_err = 1; | |
| D = 0; /* clear D */ | |
| hb_pend = 0; /* no halt br */ | |
| pcq_r = find_reg ("ISQ", NULL, dptr); | |
| if (pcq_r) | |
| pcq_r->qptr = 0; | |
| else return SCPE_IERR; | |
| sim_brk_types = sim_brk_dflt = SWMASK ('E'); | |
| return SCPE_OK; | |
| } | |
| /* Memory examine */ | |
| t_stat cpu_ex (t_value *vptr, t_addr addr, UNIT *uptr, int32 sw) | |
| { | |
| if (addr >= MEMSIZE) | |
| return SCPE_NXM; | |
| if (vptr != NULL) | |
| *vptr = M[addr] & (WM + CHAR); | |
| return SCPE_OK; | |
| } | |
| /* Memory deposit */ | |
| t_stat cpu_dep (t_value val, t_addr addr, UNIT *uptr, int32 sw) | |
| { | |
| if (addr >= MEMSIZE) | |
| return SCPE_NXM; | |
| M[addr] = val & (WM + CHAR); | |
| return SCPE_OK; | |
| } | |
| /* Memory size change */ | |
| t_stat cpu_set_size (UNIT *uptr, int32 val, char *cptr, void *desc) | |
| { | |
| int32 mc = 0; | |
| uint32 i; | |
| if ((val <= 0) || (val > MAXMEMSIZE) || ((val % 1000) != 0)) | |
| return SCPE_ARG; | |
| for (i = val; i < MEMSIZE; i++) | |
| mc = mc | M[i]; | |
| if ((mc != 0) && (!get_yn ("Really truncate memory [N]?", FALSE))) | |
| return SCPE_OK; | |
| MEMSIZE = val; | |
| for (i = MEMSIZE; i < MAXMEMSIZE; i++) | |
| M[i] = 0; | |
| if (MEMSIZE > 4000) | |
| cpu_unit.flags = cpu_unit.flags | MA; | |
| else cpu_unit.flags = cpu_unit.flags & ~MA; | |
| return SCPE_OK; | |
| } | |
| /* Set history */ | |
| t_stat cpu_set_hist (UNIT *uptr, int32 val, char *cptr, void *desc) | |
| { | |
| int32 i, lnt; | |
| t_stat r; | |
| if (cptr == NULL) { | |
| for (i = 0; i < hst_lnt; i++) | |
| hst[i].ilnt = 0; | |
| hst_p = 0; | |
| return SCPE_OK; | |
| } | |
| lnt = (int32) get_uint (cptr, 10, HIST_MAX, &r); | |
| if ((r != SCPE_OK) || (lnt && (lnt < HIST_MIN))) | |
| return SCPE_ARG; | |
| hst_p = 0; | |
| if (hst_lnt) { | |
| free (hst); | |
| hst_lnt = 0; | |
| hst = NULL; | |
| } | |
| if (lnt) { | |
| hst = (InstHistory *) calloc (lnt, sizeof (InstHistory)); | |
| if (hst == NULL) | |
| return SCPE_MEM; | |
| hst_lnt = lnt; | |
| } | |
| return SCPE_OK; | |
| } | |
| /* Show history */ | |
| t_stat cpu_show_hist (FILE *st, UNIT *uptr, int32 val, void *desc) | |
| { | |
| int32 i, k, di, lnt; | |
| char *cptr = (char *) desc; | |
| t_value sim_eval[MAX_L + 1]; | |
| t_stat r; | |
| InstHistory *h; | |
| if (hst_lnt == 0) /* enabled? */ | |
| return SCPE_NOFNC; | |
| if (cptr) { | |
| lnt = (int32) get_uint (cptr, 10, hst_lnt, &r); | |
| if ((r != SCPE_OK) || (lnt == 0)) | |
| return SCPE_ARG; | |
| } | |
| else lnt = hst_lnt; | |
| di = hst_p - lnt; /* work forward */ | |
| if (di < 0) | |
| di = di + hst_lnt; | |
| fprintf (st, "IS IR\n\n"); | |
| for (k = 0; k < lnt; k++) { /* print specified */ | |
| h = &hst[(++di) % hst_lnt]; /* entry pointer */ | |
| if (h->ilnt) { /* instruction? */ | |
| fprintf (st, "%05d ", h->is); | |
| for (i = 0; i < h->ilnt; i++) | |
| sim_eval[i] = h->inst[i]; | |
| sim_eval[h->ilnt] = WM; | |
| if ((fprint_sym (st, h->is, sim_eval, &cpu_unit, SWMASK ('M'))) > 0) { | |
| fprintf (st, "(undefined)"); | |
| for (i = 0; i < h->ilnt; i++) | |
| fprintf (st, " %02o", h->inst[i]); | |
| } | |
| fputc ('\n', st); /* end line */ | |
| } /* end else instruction */ | |
| } /* end for */ | |
| return SCPE_OK; | |
| } | |
| /* Set conversions */ | |
| t_stat cpu_set_conv (UNIT *uptr, int32 val, char *cptr, void *desc) | |
| { | |
| conv_old = val; | |
| return SCPE_OK; | |
| } | |
| /* Show conversions */ | |
| t_stat cpu_show_conv (FILE *st, UNIT *uptr, int32 val, void *desc) | |
| { | |
| if (conv_old) | |
| fputs ("Old (pre-3.5-1) conversions\n", st); | |
| else fputs ("New conversions\n", st); | |
| return SCPE_OK; | |
| } |