init commit

peak_sse2_assist.s

@@ -0,0 +1,51 @@
+# SSE2 assist routines for peakval
+# Copyright 2001 Phil Karn, KA9Q
+# May be used under the terms of the GNU Public License (GPL)
+
+	.text
+
+# Find peak absolute value in signed 16-bit input samples
+#  int peakval_sse2(signed short *in,int cnt);
+	.global peakval_sse2
+	.type peakval_sse2,@function
+	.align 16
+peakval_sse2:
+	pushl %ebp
+	movl %esp,%ebp
+	pushl %esi
+	pushl %ecx
+
+	movl 8(%ebp),%esi
+	movl 12(%ebp),%ecx
+
+	pxor %xmm7,%xmm7	# clear peak
+	
+1:	subl $8,%ecx
+	jl 2f
+	movaps (%esi),%xmm0
+	movaps %xmm0,%xmm1	
+	psraw $15,%xmm1		# xmm1 = 1's if negative, 0's if positive
+	pxor %xmm1,%xmm0	# complement negatives
+	psubw %xmm1,%xmm0	# add 1 to negatives
+	pmaxsw %xmm0,%xmm7	# store peak
+	
+	addl $16,%esi
+	jmp 1b
+
+2:	movaps %xmm7,%xmm0
+	psrldq $8,%xmm0
+	pmaxsw %xmm0,%xmm7
+	movaps %xmm7,%xmm0
+	psrlq $32,%xmm0
+	pmaxsw %xmm0,%xmm7
+	movaps %xmm7,%xmm0
+	psrlq $16,%xmm0
+	pmaxsw %xmm0,%xmm7	# min value in low word of %xmm7
+	
+	movd %xmm7,%eax
+	andl $0xffff,%eax
+
+	popl %ecx
+	popl %esi
+	popl %ebp
+	ret