mv_mix.wasm

An interactive water fountain. A realistic water source in your pocket with full control. Contro

;
;================

; eax - position
; edx - rate
; ebx - start
; ecx - number of samples to mix

ALIGN 16
PUBLIC  MV_Mix16BitMono_
MV_Mix16BitMono_:
; Two at once
        pushad
	; Thanks to Lauri Liinat for spotting this lunacy
	;mov     eax, dword ptr [esp + 0*4 + 9*4]
	;mov     edx, dword ptr [esp + 1*4 + 9*4]
	;mov     ebx, dword ptr [esp + 2*4 + 9*4]
	;mov     ecx, dword ptr [esp + 3*4 + 9*4]

        mov     ebp, eax

        mov     esi, ebx                        ; Source pointer

        ; Sample size
        mov     ebx, _MV_SampleSize
        mov     byte ptr [cpatch5+3],bl
        mov     byte ptr [cpatch6+3],bl
        add     bl,bl
        mov     byte ptr [cpatch7+2],bl

        ; Volume table ptr
        mov     ebx, _MV_LeftVolume
        mov     dword ptr [cpatch1+4],ebx
        mov     dword ptr [cpatch2+4],ebx

        ; Rate scale ptr
        mov     dword ptr [cpatch3+2],edx
        mov     dword ptr [cpatch4+2],edx

        mov     edi, _MV_MixDestination         ; Get the position to write to

        ; Number of samples to mix
        shr     ecx, 1                          ; double sample count
        cmp     ecx, 0
        je      exit16M

;     eax - scratch
;     ebx - scratch
;     edx - scratch
;     ecx - count
;     edi - destination
;     esi - source
;     ebp - frac pointer
; cpatch1 - volume table
; cpatch2 - volume table
; cpatch3 - sample rate
; cpatch4 - sample rate

        mov     eax,ebp                         ; begin calculating first sample
        add     ebp,edx                         ; advance frac pointer
        shr     eax,16                          ; finish calculation for first sample

        mov     ebx,ebp                         ; begin calculating second sample
        add     ebp,edx                         ; advance frac pointer
        shr     ebx,16                          ; finish calculation for second sample

        movzx   eax, byte ptr [esi+eax]         ; get first sample
        movzx   ebx, byte ptr [esi+ebx]         ; get second sample

;ALIGN 4
mix16Mloop:
        movsx   edx, word ptr [edi]             ; get current sample from destination
cpatch1:
        movsx   eax, word ptr [2*eax+12345678h] ; volume translate first sample
cpatch2:
        movsx   ebx, word ptr [2*ebx+12345678h] ; volume translate second sample
        add     eax, edx                        ; mix first sample
cpatch5:
        movsx   edx, word ptr [edi + 2]         ; get current sample from destination

        cmp     eax, -32768                     ; Harsh clip sample
        jge     short m16skip1
        mov     eax, -32768
        jmp     short m16skip2
m16skip1:
        cmp     eax, 32767
        jle     short m16skip2
        mov     eax, 32767
m16skip2:
        add     ebx, edx                        ; mix second sample
        mov     [edi], ax                       ; write new sample to destination
        mov     edx, ebp                        ; begin calculating third sample

        cmp     ebx, -32768                     ; Harsh clip sample
        jge     short m16skip3
        mov     ebx, -32768
        jmp     short m16skip4
m16skip3:
        cmp     ebx, 32767
        jle     short m16skip4
        mov     ebx, 32767
m16skip4:
cpatch3:
        add     ebp,12345678h                   ; advance frac pointer
        shr     edx, 16                         ; finish calculation for third sample
        mov     eax, ebp                        ; begin calculating fourth sample
cpatch6:
        mov     [edi + 2], bx                   ; write new sample to destination
        shr     eax, 16                         ; finish calculation for fourth sample

cpatch4:
        add     ebp,12345678h                   ; advance frac pointer
        movzx   ebx, byte ptr [esi+eax]         ; get fourth sample
cpatch7:
        add     edi, 4                          ; move destination to third sample
        movzx   eax, byte ptr [esi+edx]         ; get third sample
        dec     ecx                             ; decrement count
        jnz     mix16Mloop                      ; loop

        mov     _MV_MixDestination, edi         ; Store the current write position
        mov     _MV_MixPosition, ebp            ; return position
EXIT16M:
        popad
        ret


;================
;
; MV_Mix16BitStereo
;
;================

; eax - position
; edx - rate
; ebx - start
; ecx - number of samples to mix

ALIGN 16
PUBLIC  MV_Mix16BitStereo_
MV_Mix16BitStereo_:
        pushad
	; Thanks to Lauri Liinat for spotting this lunacy
	;mov     eax, dword ptr [esp + 0*4 + 9*4]
	;mov     edx, dword ptr [esp + 1*4 + 9*4]
	;mov     ebx, dword ptr [esp + 2*4 + 9*4]
	;mov     ecx, dword ptr [esp + 3*4 + 9*4]
	
        mov     ebp, eax

        mov     esi, ebx                        ; Source pointer

        ; Sample size
        mov     ebx, _MV_SampleSize
        mov     byte ptr [dpatch6+2],bl

        ; Right channel offset
        mov     ebx, _MV_RightChannelOffset
        mov     dword ptr [dpatch4+3],ebx
        mov     dword ptr [dpatch5+3],ebx

        ; Volume table ptr
        mov     ebx, _MV_LeftVolume
        mov     dword ptr [dpatch1+4],ebx

        mov     ebx, _MV_RightVolume
        mov     dword ptr [dpatch2+4],ebx

        ; Rate scale ptr
        mov     dword ptr [dpatch3+2],edx

        mov     edi, _MV_MixDestination         ; Get the position to write to

        ; Number of samples to mix
        cmp     ecx, 0
        je      exit16S

;     eax - scratch
;     ebx - scratch
;     edx - scratch
;     ecx - count
;     edi - destination
;     esi - source
;     ebp - frac pointer
; dpatch1 - left volume table
; dpatch2 - right volume table
; dpatch3 - sample rate

        mov     eax,ebp                         ; begin calculating first sample
        shr     eax,16                          ; finish calculation for first sample

        movzx   ebx, byte ptr [esi+eax]         ; get first sample

;ALIGN 4
mix16Sloop:
dpatch1:
        movsx   eax, word ptr [2*ebx+12345678h] ; volume translate left sample
        movsx   edx, word ptr [edi]             ; get current sample from destination
dpatch2:
        movsx   ebx, word ptr [2*ebx+12345678h] ; volume translate right sample
        add     eax, edx                        ; mix left sample
dpatch3:
        add     ebp,12345678h                   ; advance frac pointer
dpatch4:
        movsx   edx, word ptr [edi+12345678h]   ; get current sample from destination

        cmp     eax, -32768                     ; Harsh clip sample
        jge     short s16skip1
        mov     eax, -32768
        jmp     short s16skip2
s16skip1:
        cmp     eax, 32767
        jle     short s16skip2
        mov     eax, 32767
s16skip2:
        add     ebx, edx                        ; mix right sample
        mov     [edi], ax                       ; write left sample to destination

        cmp     ebx, -32768                     ; Harsh clip sample
        jge     short s16skip3
        mov     ebx, -32768
        jmp     short s16skip4
s16skip3:
        cmp     ebx, 32767
        jle     short s16skip4
        mov     ebx, 32767
s16skip4:

        mov     edx, ebp                        ; begin calculating second sample
dpatch5:
        mov     [edi+12345678h], bx             ; write right sample to destination
        shr     edx, 16                         ; finish calculation for second sample
dpatch6:
        add     edi, 4                          ; move destination to second sample
        movzx   ebx, byte ptr [esi+edx]         ; get second sample
        dec     ecx                             ; decrement count
        jnz     mix16Sloop                      ; loop

        mov     _MV_MixDestination, edi         ; Store the current write position
        mov     _MV_MixPosition, ebp            ; return position
exit16S:
        popad
        ret

CODE ENDS
END