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Useful Code Snippets: Difference between revisions
From SnesLab
Nambona890 (talk | contribs) m (→65c816 S-CPU) |
Vitor Vilela (talk | contribs) m (Ladida is silly) |
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; 16bit * 16bit Multiplication SA-1 version | ; 16bit * 16bit Multiplication SA-1 version | ||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | ||
; | ; Parameters | ||
; $00-$01 : Multiplicand | ; $00-$01 : Multiplicand | ||
; $02-$03 : Multiplier | ; $02-$03 : Multiplier | ||
Revision as of 01:17, 26 July 2019
Useful code snippets for the 65c816 ASM and general SNES hardware.
65c816 S-CPU
Wait for H-Blank
- BIT $4212 BVS - - BIT $4212 BVC -
Inverse the accumulator (8-bit)
EOR #$FF INC
Inverse the accumulator (16-bit)
EOR #$FFFF INC
65c816 SA-1 CPU
Unsigned 16 bit x 16 bit = 32 bit multiplication
by Akaginite
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; 16bit * 16bit Multiplication SA-1 version ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Parameters ; $00-$01 : Multiplicand ; $02-$03 : Multiplier ; Return values ; $04-$07 : Product ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; MathMul16_16: STZ $2250 REP #$20 LDA $00 STA $2251 ASL A LDA $02 STA $2253 BCS + LDA.w #$0000 + BIT $02 BPL + CLC ADC $00 + CLC ADC $2308 STA $06 LDA $2306 STA $04 SEP #$20 RTS