Created
January 23, 2021 06:49
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6502 assembly - simple RAND subroutine
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| rand equ $04 | |
| ;uint8_t next_rnd(void) | |
| ;{ | |
| ; static uint8_t rnd; | |
| ; rnd = rnd * 5 + 17; | |
| ; return rnd; | |
| ;} | |
| ; returns a pseudo rand store at memory location: rand | |
| next_rand: | |
| lda rand | |
| asl ; A = RND * 2 | |
| asl ; A = RND * 4 | |
| clc | |
| adc rand ; A = RND * 5 | |
| clc | |
| adc #17 ; A = RND * 5 + 17 | |
| sta rand | |
| rts |
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http://www.dabeaz.com/superboard/asm6502.py