| prime number generator using the sieve of eratosthenes | |
| converted to ibm 650 floating poing interpretive system (is) | |
| uses two extra o2 codes: o2=800 (set lbox) and o2=453 (tr zero) | |
| warning: comments are allowed past column 28 but some characters | |
| are forbidden: uppercase letters, question mark, exclamation, number char, | |
| ampersand char. if these chars are used, the line (i.e. the card for this | |
| line) will be interpreted as a load card, and program will crash on trying | |
| to execute it. | |
| 100 -9 000 201 400 initp -move i1 prime initp: prime[c]=1 | |
| 101 +0 001 050 100 loop c 050 initp c++; if c<50 goto initp | |
| 102 +9 000 201 300 move i1 num num=1 | |
| 103 +1 300 201 300 loop1 add num i1 num loop1: num++ | |
| 104 +2 300 203 000 sub num i50 last | |
| 105 +0 201 120 106 tr sgn loope cont if num >= 50 goto loope | |
| 106 +0 800 002 300 set lbox b num b=num | |
| 107 -9 000 400 000 -move prime last last=prime[b] | |
| 108 +0 453 103 110 tr zero loop1 cont if last = 0 goto loop1 | |
| 110 +9 000 300 301 move num mult mult=num | |
| 111 +1 300 301 301 loop2 add num mult mult loop2: mult=mult+num | |
| 112 +2 301 203 000 sub mult i50 last | |
| 113 +0 201 103 114 tr sgn loop1 cont if mult >= 50 goto loop1 (go to b if +, go to c if -) | |
| 114 +0 800 003 301 set lbox c mult c=mult | |
| 115 -9 000 200 400 -move zero prime prime[c]=0 | |
| 116 +0 203 000 111 tr loop2 goto loop2 | |
| 120 +9 000 201 300 loope move i1 num loope: num=1 | |
| 121 +0 800 002 202 set lbox b i2 b=2 | |
| 122 +1 300 201 300 prt1 add num i1 num prt1: num++ | |
| 123 -9 000 400 000 -move prime last last=prime[b] | |
| 124 +0 453 127 126 tr zero prt2 cont if last = 0 goto prt2 | |
| 126 +0 410 300 300 pch num num punch num | |
| 127 +0 010 050 122 prt2 loop b 050 prt1 prt2: b++; if b<50 goto prt1 | |
| 128 +0 000 000 000 unc stop end | |
| constants | |
| 200 +0 0000000 50 zero | |
| 201 +1 0000000 50 i1 | |
| 202 +2 0000000 50 i2 | |
| 203 +5 0000000 51 i50 | |
| variables | |
| 300 +0 0000000 50 num current number to check for being prime | |
| 301 +0 0000000 50 mult multiple | |
| 400 +0 0000000 50 prime array of numbers 400-449 | |
| 100 program start address | |