ref: a398442d41ed928c12632909a02fd5f3052b7d27
dir: /Game/src/audiolib/mvreverb.asm/
IDEAL
p386
MODEL flat
dataseg
CODESEG
MASM
ALIGN 4
;================
;
; MV_16BitReverb
;
;================
; eax - source position
; edx - destination position
; ebx - Volume table
; ecx - number of samples
PROC MV_16BitReverb_
PUBLIC MV_16BitReverb_
mov esi, eax
lea edi, [edx - 2]
ALIGN 4
rev16loop:
movzx eax, word ptr [esi] ; get sample
add edi, 2
movzx edx, ah
sub ah, ah
movsx eax, byte ptr [2*eax+ebx+1] ; volume translate low byte of sample
xor edx, 80h
movsx edx, word ptr [2*edx+ebx] ; volume translate high byte of sample
add esi, 2
lea eax, [ eax + edx + 80h ] ; mix high byte of sample
dec ecx ; decrement count
mov [edi], ax ; write new sample to destination
jnz rev16loop ; loop
ret
ENDP MV_16BitReverb_
;================
;
; MV_8BitReverb
;
;================
; eax - source position
; edx - destination position
; ebx - Volume table
; ecx - number of samples
PROC MV_8BitReverb_
PUBLIC MV_8BitReverb_
mov esi, eax
lea edi, [edx - 1]
xor eax, eax
ALIGN 4
rev8loop:
; movzx eax, byte ptr [esi] ; get sample
mov al, byte ptr [esi] ; get sample
inc edi
; movsx eax, byte ptr [2*eax+ebx] ; volume translate sample
mov al, byte ptr [2*eax+ebx] ; volume translate sample
inc esi
; add eax, 80h
add al, 80h
dec ecx ; decrement count
mov [edi], al ; write new sample to destination
jnz rev8loop ; loop
ret
ENDP MV_8BitReverb_
;================
;
; MV_16BitReverbFast
;
;================
; eax - source position
; edx - destination position
; ebx - number of samples
; ecx - shift
PROC MV_16BitReverbFast_
PUBLIC MV_16BitReverbFast_
mov esi, eax
mov eax,OFFSET rpatch16+3
mov [eax],cl
lea edi, [edx - 2]
ALIGN 4
frev16loop:
mov ax, word ptr [esi] ; get sample
add edi, 2
rpatch16:
sar ax, 5 ;;;;Add 1 before shift
add esi, 2
mov [edi], ax ; write new sample to destination
dec ebx ; decrement count
jnz frev16loop ; loop
ret
ENDP MV_16BITREVERBFAST_
;================
;
; MV_8BitReverbFast
;
;================
; eax - source position
; edx - destination position
; ebx - number of samples
; ecx - shift
PROC MV_8BitReverbFast_
PUBLIC MV_8BitReverbFast_
mov esi, eax
mov eax,OFFSET rpatch8+2
mov edi, edx
mov edx, 80h
mov [eax],cl
mov eax, 80h
shr eax, cl
dec edi
sub edx, eax
ALIGN 4
frev8loop:
mov al, byte ptr [esi] ; get sample
inc esi
mov ecx, eax
inc edi
rpatch8:
shr eax, 3
xor ecx, 80h ; flip the sign bit
shr ecx, 7 ; shift the sign down to 1
add eax, edx
add eax, ecx ; add sign bit to round to 0
dec ebx ; decrement count
mov [edi], al ; write new sample to destination
jnz frev8loop ; loop
ret
ENDP MV_8BITREVERBFAST_
ENDS
END