AMD 250 manual 223

25112 Rev. 3.06 September 2005 Software Optimization Guide for AMD64 Processors

mov [esp+4*ebx+12], esi		;	Move into address esp+4*ebx the single-precision
mov [esp+4*ebx+8],	edi	;	floating-point sign mask.
mov [esp+4*ebx+4],	esi

mov [esp+4*ebx], edi ;==============================================================================

;THE 4 ASM LINES BELOW LOAD THE FUNCTION's ARGUMENTS INTO GENERAL-PURPOSE

;REGISTERS (GPRS)

;esi = address of array "x"

;edi = address of array "y"

;ecx = # of cmplx products to compute

;eax = address of product to which results are stored ;==============================================================================

mov esi, [ebp+8]			; esi = ->x
mov edi, [ebp+12]			; edi = ->y
mov	ecx,	[ebp+16]	; ecx	=	num_cmplx_elem
mov	eax,	[ebp+20]	; eax	=	->prod

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

;THE 6 ASM LINES BELOW OFFSET THE ADDRESS TO THE ARRAYS x[] AND y[] SUCH

;THAT THEY CAN BE ACCESSED IN THE MOST EFFICIENT MANNER AS ILLUSTRATED

;BELOW IN THE LOOP mult4cmplxnum_loop WITH THE MINIMUM NUMBER OF

;ADDRESS INCREMENTS ;==============================================================================

mov edx, ecx	;	edx	= num_cmplx_elem
neg ecx	;	ecx	= -num_cmplx_elem
shl edx, 3	; edx =		8 * num_cmplx_elem	= # bytes	in x[] and y[] to multiply
add esi, edx	; esi =		-> to last element	of x[] to	multiply
add edi, edx	; edi =		-> to last element	of y[] to	multiply
add eax, edx	; eax =		-> end of prod[] to calculate

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

;THIS LOOP MULTIPLIES 4 COMPLEX #s FROM "x[]" UPON 4 COMPLEX #s FROM "y[]"

;AND RETURNS THE PRODUCT IN "prod[]". ;==============================================================================

ALIGN 16	; Align		address of loop to a 16-byte boundary.
eight_cmplx_prod_loop:
movaps xmm0, [esi+ecx*8]		;	xmm0=[x1i,x1r,x0i,x0r]
movaps xmm1, [esi+ecx*8+16]		;	xmm1=[x3i,x3r,x2i,x2r]
movaps xmm4, [edi+ecx*8]		;	xmm4=[y1i,y1r,y0i,y0r]
movaps xmm5, [edi+ecx*8+16]		;	xmm5=[y3i,y3r,y2i,y2r]
movaps xmm2, xmm0		;	xmm2=[x1i,x1r,x0i,x0r]
movaps xmm3, xmm1		;	xmm3=[x3i,x3r,x2i,x2r]
movaps xmm6, xmm4		;	xmm6=[y1i,y1r,y0i,y0r]
movaps xmm7, xmm5		;	xmm7=[y3i,y3r,y2i,y2r]
shufps xmm0, xmm0, 10100000b		;	xmm0=[x1r,x1r,x0r,x0r]
shufps xmm1, xmm1, 10100000b		;	xmm1=[x3r,x3r,x2r,x2r]
shufps xmm2, xmm2, 11110101b		;	xmm2=[x1i,x1i,x0i,x0i]
shufps	xmm3, xmm3, 11110101b	;	xmm3=[x3i,x3i,x2i,x2i]
xorps	xmm6, [esp+4*ebx]	;	xmm6=[-y1i,y1r,-y0i,y0r]
xorps	xmm7, [esp+4*ebx]	;	xmm7=[-y3i,y3r,-y2i,y2r]
mulps xmm0, xmm4		;	xmm0=[x1r*y1i,x1r*y1r,x0r*y0i,x0r*y0r]
mulps xmm1, xmm5		;	xmm1=[x3r*y3i,x3r*y3r,x2r*y2i,x2r*y2r]
shufps xmm7, xmm7, 10110001b		;	xmm7=[y3r,-y3i,y2r,-y2i]

Chapter 9 Optimizing with SIMD Instructions 223