50 lines
925 B
ArmAsm
50 lines
925 B
ArmAsm
# SSE assist routines for peakval
|
|
# Copyright 2001 Phil Karn, KA9Q
|
|
# May be used under the terms of the GNU Lesser General Public License (LGPL)
|
|
|
|
.text
|
|
|
|
# Find peak absolute value in signed 16-bit input samples
|
|
# int peakval_sse(signed short *in,int cnt);
|
|
.global peakval_sse
|
|
.type peakval_sse,@function
|
|
.align 16
|
|
peakval_sse:
|
|
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
|
|
|
|
emms
|
|
popl %ecx
|
|
popl %esi
|
|
popl %ebp
|
|
ret
|