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.. | ||
docs | ||
dump.bas | ||
EA.PT3 | ||
empty.dsk | ||
gr_fast_clear.s | ||
HELLO | ||
hello.bas | ||
interrupt_handler.s | ||
Makefile | ||
pt3_dumper.s | ||
pt3_lib.s | ||
pt3_player.dsk | ||
pt3_player.s | ||
qkumba_rts.s | ||
README.pt3 | ||
song_list.inc | ||
SR.PT3 | ||
text_print.s | ||
TODO | ||
VC.PT3 | ||
zp.inc |
PT3_player ASR = CMP #$80 / ROR Notes: signed 8-bit comparison see http://6502.org/tutorials/compare_beyond.html#2.2 SEC ; prepare carry for SBC SBC NUM ; A-NUM BVC LABEL ; if V is 0, N eor V = N, otherwise N eor V = N eor 1 EOR #$80 ; A = A eor $80, and N = N eor 1 LABEL If the N flag is 1, then A (signed) < NUM (signed) and BMI will branch If the N flag is 0, then A (signed) >= NUM (signed) and BPL will branch