raze/polymer/eduke32/source/jaudiolib/mvreverb.wasm

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.586P
CODE SEGMENT PUBLIC USE32 'DATA'
ASSUME cs:CODE,ds:CODE
;================
;
; MV_16BitReverb
;
;================
; eax - source position
; edx - destination position
; ebx - Volume table
; ecx - number of samples
ALIGN 16
PUBLIC MV_16BitReverb_
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
;================
;
; MV_8BitReverb
;
;================
; eax - source position
; edx - destination position
; ebx - Volume table
; ecx - number of samples
ALIGN 16
PUBLIC MV_8BitReverb_
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
;================
;
; MV_16BitReverbFast
;
;================
; eax - source position
; edx - destination position
; ebx - number of samples
; ecx - shift
ALIGN 16
PUBLIC MV_16BitReverbFast_
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
;================
;
; MV_8BitReverbFast
;
;================
; eax - source position
; edx - destination position
; ebx - number of samples
; ecx - shift
ALIGN 16
PUBLIC MV_8BitReverbFast_
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
CODE ENDS
END