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cc65/libsrc/vic20/randomize.s
Greg King 031bd2ebf0 Fixed the random-seed generators for the Commodore targets.
They use a byte from the time counter; but, it is stored in big-endian order.
2015-09-11 10:03:07 -04:00

23 lines
655 B
ArmAsm

;
; 2002-11-05, Ullrich von Bassewitz
; 2015-09-11, Greg King
;
; void _randomize (void);
; /* Initialize the random number generator */
;
.export __randomize
.import _srand
.include "vic20.inc"
__randomize:
lda VIC_LINES ; Get overflow bit
asl a ; Shift bit 7 into carry
lda VIC_HLINE ; Get bit 1-8 of rasterline
rol a ; Use bit 0-7
tax ; Use VIC rasterline as high byte
lda TIME+2 ; Use 60HZ clock as low byte
jmp _srand ; Initialize generator