ALIGN 4
invm	dd	0,0,0,0,0,0 ,0,0
	dd	0,0,0,0,0,0 ,0,0
	dd	0,0,0,0,0,0 ,0,0
	
invswap MACRO zl1,zl2
	zzz=0
	REPT 6
	mov	eax,cs:invm[zl1*32+zzz]
	xchg	eax,cs:invm[zl2*32+zzz]
	mov	cs:invm[zl1*32+zzz],eax
	zzz=zzz+4
	ENDM
	ENDM

submacro MACRO zsub,zto,zmul,zdiv
	;row[to]-=row[add]*zmul/zdiv
	zzz=0
	REPT 6
	mov	eax,cs:invm[zzz+zsub*32]
	imul	zmul
	idiv	zdiv
	sub	cs:invm[zzz+zto*32],eax
	zzz=zzz+4
	ENDM
	ENDM

addmacro MACRO zadd,zto
	;row[to]+=row[add]
	zzz=0
	REPT 6
	mov	eax,cs:invm[zzz+zadd*32]
	add	cs:invm[zzz+zto*32],eax
	zzz=zzz+4
	ENDM
	ENDM

scalemacro MACRO zto,zdiv
	mov	ecx,32767
	zzz=0
	REPT 6
	mov	eax,cs:invm[zzz+zto*32]
	imul	ecx
	idiv	zdiv
	mov	cs:invm[zzz+zto*32],eax
	zzz=zzz+4
	ENDM
	ENDM

;entry: es:di=matrix1
; exit: es:di=matrix1 (overwritten by it's inverse)
invmatrix PROC NEAR
	xor	ecx,ecx
	mov	ebx,32767
	movsx	eax,word ptr es:[di+0]
	mov	cs:invm[0],eax
	movsx	eax,word ptr es:[di+2]
	mov	cs:invm[4],eax
	movsx	eax,word ptr es:[di+4]
	mov	cs:invm[8],eax
	mov	cs:invm[12],ebx
	mov	cs:invm[16],ecx
	mov	cs:invm[20],ecx
	movsx	eax,word ptr es:[di+6]
	mov	cs:invm[32+0],eax
	movsx	eax,word ptr es:[di+8]
	mov	cs:invm[32+4],eax
	movsx	eax,word ptr es:[di+10]
	mov	cs:invm[32+8],eax
	mov	cs:invm[32+12],ecx
	mov	cs:invm[32+16],ebx
	mov	cs:invm[32+20],ecx
	movsx	eax,word ptr es:[di+12]
	mov	cs:invm[64+0],eax
	movsx	eax,word ptr es:[di+14]
	mov	cs:invm[64+4],eax
	movsx	eax,word ptr es:[di+16]
	mov	cs:invm[64+8],eax
	mov	cs:invm[64+12],ecx
	mov	cs:invm[64+16],ecx
	mov	cs:invm[64+20],ebx
	;
	int 3
	mov	ecx,cs:invm[4*0+32*0]
	mov	ebx,cs:invm[4*0+32*1]
	mov	eax,cs:invm[4*0+32*2]
	or	ecx,ecx
	jnz	@@1
	or	ebx,ebx
	jnz	@@2
	or	eax,eax
	jz	@@0
	mov	ecx,eax
	addmacro 0,2
	jmp	@@1
@@2:	mov	ecx,ebx
	addmacro 0,1
@@1:	mov	ebx,cs:invm[4*0+32*1]
	or	ebx,ebx
	jz	@@3
	submacro 0,1,ebx,ecx
@@3:	mov	ebx,cs:invm[4*0+32*2]
	or	ebx,ebx
	jz	@@4
	submacro 0,2,ebx,ecx
@@4:
	mov	ecx,cs:invm[4*1+32*1]
	mov	ebx,cs:invm[4*1+32*2]
	or	ecx,ecx
	jnz	@@b1
	or	ebx,ebx
	jz	@@0
	mov	ecx,ebx
	addmacro 1,2
@@b1:	mov	ebx,cs:invm[4*1+32*0]
	or	ebx,ebx
	jz	@@b3
	submacro 1,0,ebx,ecx
@@b3:	mov	ebx,cs:invm[4*1+32*2]
	or	ebx,ebx
	jz	@@b4
	submacro 1,2,ebx,ecx
@@b4:
	mov	ecx,cs:invm[4*2+32*2]
	or	ecx,ecx
	jz	@@0
	mov	ebx,cs:invm[4*2+32*0]
	or	ebx,ebx
	jz	@@c3
	submacro 2,0,ebx,ecx
@@c3:	mov	ebx,cs:invm[4*2+32*1]
	or	ebx,ebx
	jz	@@c4
	submacro 2,1,ebx,ecx
@@c4:
	mov	ebx,cs:invm[4*0+32*0]
	scalemacro 0,ebx
	mov	ebx,cs:invm[4*1+32*1]
	scalemacro 1,ebx
	mov	ebx,cs:invm[4*2+32*2]
	scalemacro 2,ebx

	int 3
	mov	ax,word ptr cs:invm[12+4*0+32*0]
	mov	es:[di+0],ax
	mov	ax,word ptr cs:invm[12+4*1+32*0]
	mov	es:[di+2],ax
	mov	ax,word ptr cs:invm[12+4*2+32*0]
	mov	es:[di+4],ax
	mov	ax,word ptr cs:invm[12+4*0+32*1]
	mov	es:[di+6],ax
	mov	ax,word ptr cs:invm[12+4*1+32*1]
	mov	es:[di+8],ax
	mov	ax,word ptr cs:invm[12+4*2+32*1]
	mov	es:[di+10],ax
	mov	ax,word ptr cs:invm[12+4*0+32*2]
	mov	es:[di+12],ax
	mov	ax,word ptr cs:invm[12+4*1+32*2]
	mov	es:[di+14],ax
	mov	ax,word ptr cs:invm[12+4*2+32*2]
	mov	es:[di+16],ax
@@0:	ret
invmatrix ENDP