diff options
Diffstat (limited to 'test/popcnt2.s')
| -rw-r--r-- | test/popcnt2.s | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/test/popcnt2.s b/test/popcnt2.s new file mode 100644 index 0000000..aaa4743 --- /dev/null +++ b/test/popcnt2.s @@ -0,0 +1,41 @@ +; Register only version of popcnt. + +.org $1000 + +popcnt: + ldy #0 ; Reset bit count. + cmp #0 ; Set the status flags. +@loop: + beq @end ; There are no more one bits left, so we're done. + tab ; Place the value in the B register. + deb ; Decrement the temp value by one. + iny ; Increment the bit count. + aba ; AND value with value-1. + bra @loop ; Keep looping. +@end: + tya ; Return the bit count. + rts ; End of popcnt. + + +reset: + cps ; Boilerplate reset code. + ldx.w #$FFFF ; + txs ; + and #0 ; Reset A. + tab ; Reset B. + tax ; Reset X. + tay ; Reset Y. +main: + pha.q ; Save A. + jsr popcnt ; Get population count. + tay ; Save it in Y. + pla.q ; Get A back. + inc ; Increment A by one. + bra main ; Keep looping. + + +.org $FFC0 +.qword reset + +a +d |