blob: 827c800459140fbe8e0938256077a98a0e768884 [file] [log] [blame]
# SSE assist routines for peakval
# Copyright 2001 Phil Karn, KA9Q
# May be used under the terms of the GNU Lesser General Public License (LGPL)
# Find peak absolute value in signed 16-bit input samples
# int peakval_sse_assist(signed short *in,int cnt);
.global peakval_sse_assist
.type peakval_sse_assist,@function
.align 16
pushl %ebp
movl %esp,%ebp
pushl %esi
pushl %ecx
movl 8(%ebp),%esi
movl 12(%ebp),%ecx
pxor %mm7,%mm7 # clear peak
1: subl $4,%ecx
jl 2f
movq (%esi),%mm0
movq %mm0,%mm1
psraw $15,%mm1 # mm1 = 1's if negative, 0's if positive
pxor %mm1,%mm0 # complement negatives
psubw %mm1,%mm0 # add 1 to negatives
pmaxsw %mm0,%mm7 # store peak
addl $8,%esi
jmp 1b
2: movq %mm7,%mm0
psrlq $32,%mm0
pmaxsw %mm0,%mm7
movq %mm7,%mm0
psrlq $16,%mm0
pmaxsw %mm0,%mm7 # min value in low word of %mm7
movd %mm7,%eax
andl $0xffff,%eax
popl %ecx
popl %esi
popl %ebp