summaryrefslogtreecommitdiffstats
path: root/media/libjpeg/simd/i386/jidctflt-3dn.asm
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:22:09 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:22:09 +0000
commit43a97878ce14b72f0981164f87f2e35e14151312 (patch)
tree620249daf56c0258faa40cbdcf9cfba06de2a846 /media/libjpeg/simd/i386/jidctflt-3dn.asm
parentInitial commit. (diff)
downloadfirefox-43a97878ce14b72f0981164f87f2e35e14151312.tar.xz
firefox-43a97878ce14b72f0981164f87f2e35e14151312.zip
Adding upstream version 110.0.1.upstream/110.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'media/libjpeg/simd/i386/jidctflt-3dn.asm')
-rw-r--r--media/libjpeg/simd/i386/jidctflt-3dn.asm451
1 files changed, 451 insertions, 0 deletions
diff --git a/media/libjpeg/simd/i386/jidctflt-3dn.asm b/media/libjpeg/simd/i386/jidctflt-3dn.asm
new file mode 100644
index 0000000000..87951910d8
--- /dev/null
+++ b/media/libjpeg/simd/i386/jidctflt-3dn.asm
@@ -0,0 +1,451 @@
+;
+; jidctflt.asm - floating-point IDCT (3DNow! & MMX)
+;
+; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
+; Copyright (C) 2016, D. R. Commander.
+;
+; Based on the x86 SIMD extension for IJG JPEG library
+; Copyright (C) 1999-2006, MIYASAKA Masaru.
+; For conditions of distribution and use, see copyright notice in jsimdext.inc
+;
+; This file should be assembled with NASM (Netwide Assembler),
+; can *not* be assembled with Microsoft's MASM or any compatible
+; assembler (including Borland's Turbo Assembler).
+; NASM is available from http://nasm.sourceforge.net/ or
+; http://sourceforge.net/project/showfiles.php?group_id=6208
+;
+; This file contains a floating-point implementation of the inverse DCT
+; (Discrete Cosine Transform). The following code is based directly on
+; the IJG's original jidctflt.c; see the jidctflt.c for more details.
+
+%include "jsimdext.inc"
+%include "jdct.inc"
+
+; --------------------------------------------------------------------------
+ SECTION SEG_CONST
+
+ alignz 32
+ GLOBAL_DATA(jconst_idct_float_3dnow)
+
+EXTN(jconst_idct_float_3dnow):
+
+PD_1_414 times 2 dd 1.414213562373095048801689
+PD_1_847 times 2 dd 1.847759065022573512256366
+PD_1_082 times 2 dd 1.082392200292393968799446
+PD_2_613 times 2 dd 2.613125929752753055713286
+PD_RNDINT_MAGIC times 2 dd 100663296.0 ; (float)(0x00C00000 << 3)
+PB_CENTERJSAMP times 8 db CENTERJSAMPLE
+
+ alignz 32
+
+; --------------------------------------------------------------------------
+ SECTION SEG_TEXT
+ BITS 32
+;
+; Perform dequantization and inverse DCT on one block of coefficients.
+;
+; GLOBAL(void)
+; jsimd_idct_float_3dnow(void *dct_table, JCOEFPTR coef_block,
+; JSAMPARRAY output_buf, JDIMENSION output_col)
+;
+
+%define dct_table(b) (b) + 8 ; void *dct_table
+%define coef_block(b) (b) + 12 ; JCOEFPTR coef_block
+%define output_buf(b) (b) + 16 ; JSAMPARRAY output_buf
+%define output_col(b) (b) + 20 ; JDIMENSION output_col
+
+%define original_ebp ebp + 0
+%define wk(i) ebp - (WK_NUM - (i)) * SIZEOF_MMWORD
+ ; mmword wk[WK_NUM]
+%define WK_NUM 2
+%define workspace wk(0) - DCTSIZE2 * SIZEOF_FAST_FLOAT
+ ; FAST_FLOAT workspace[DCTSIZE2]
+
+ align 32
+ GLOBAL_FUNCTION(jsimd_idct_float_3dnow)
+
+EXTN(jsimd_idct_float_3dnow):
+ push ebp
+ mov eax, esp ; eax = original ebp
+ sub esp, byte 4
+ and esp, byte (-SIZEOF_MMWORD) ; align to 64 bits
+ mov [esp], eax
+ mov ebp, esp ; ebp = aligned ebp
+ lea esp, [workspace]
+ push ebx
+; push ecx ; need not be preserved
+; push edx ; need not be preserved
+ push esi
+ push edi
+
+ get_GOT ebx ; get GOT address
+
+ ; ---- Pass 1: process columns from input, store into work array.
+
+; mov eax, [original_ebp]
+ mov edx, POINTER [dct_table(eax)] ; quantptr
+ mov esi, JCOEFPTR [coef_block(eax)] ; inptr
+ lea edi, [workspace] ; FAST_FLOAT *wsptr
+ mov ecx, DCTSIZE/2 ; ctr
+ alignx 16, 7
+.columnloop:
+%ifndef NO_ZERO_COLUMN_TEST_FLOAT_3DNOW
+ mov eax, dword [DWBLOCK(1,0,esi,SIZEOF_JCOEF)]
+ or eax, dword [DWBLOCK(2,0,esi,SIZEOF_JCOEF)]
+ jnz short .columnDCT
+
+ pushpic ebx ; save GOT address
+ mov ebx, dword [DWBLOCK(3,0,esi,SIZEOF_JCOEF)]
+ mov eax, dword [DWBLOCK(4,0,esi,SIZEOF_JCOEF)]
+ or ebx, dword [DWBLOCK(5,0,esi,SIZEOF_JCOEF)]
+ or eax, dword [DWBLOCK(6,0,esi,SIZEOF_JCOEF)]
+ or ebx, dword [DWBLOCK(7,0,esi,SIZEOF_JCOEF)]
+ or eax, ebx
+ poppic ebx ; restore GOT address
+ jnz short .columnDCT
+
+ ; -- AC terms all zero
+
+ movd mm0, dword [DWBLOCK(0,0,esi,SIZEOF_JCOEF)]
+
+ punpcklwd mm0, mm0
+ psrad mm0, (DWORD_BIT-WORD_BIT)
+ pi2fd mm0, mm0
+
+ pfmul mm0, MMWORD [MMBLOCK(0,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+
+ movq mm1, mm0
+ punpckldq mm0, mm0
+ punpckhdq mm1, mm1
+
+ movq MMWORD [MMBLOCK(0,0,edi,SIZEOF_FAST_FLOAT)], mm0
+ movq MMWORD [MMBLOCK(0,1,edi,SIZEOF_FAST_FLOAT)], mm0
+ movq MMWORD [MMBLOCK(0,2,edi,SIZEOF_FAST_FLOAT)], mm0
+ movq MMWORD [MMBLOCK(0,3,edi,SIZEOF_FAST_FLOAT)], mm0
+ movq MMWORD [MMBLOCK(1,0,edi,SIZEOF_FAST_FLOAT)], mm1
+ movq MMWORD [MMBLOCK(1,1,edi,SIZEOF_FAST_FLOAT)], mm1
+ movq MMWORD [MMBLOCK(1,2,edi,SIZEOF_FAST_FLOAT)], mm1
+ movq MMWORD [MMBLOCK(1,3,edi,SIZEOF_FAST_FLOAT)], mm1
+ jmp near .nextcolumn
+ alignx 16, 7
+%endif
+.columnDCT:
+
+ ; -- Even part
+
+ movd mm0, dword [DWBLOCK(0,0,esi,SIZEOF_JCOEF)]
+ movd mm1, dword [DWBLOCK(2,0,esi,SIZEOF_JCOEF)]
+ movd mm2, dword [DWBLOCK(4,0,esi,SIZEOF_JCOEF)]
+ movd mm3, dword [DWBLOCK(6,0,esi,SIZEOF_JCOEF)]
+
+ punpcklwd mm0, mm0
+ punpcklwd mm1, mm1
+ psrad mm0, (DWORD_BIT-WORD_BIT)
+ psrad mm1, (DWORD_BIT-WORD_BIT)
+ pi2fd mm0, mm0
+ pi2fd mm1, mm1
+
+ pfmul mm0, MMWORD [MMBLOCK(0,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+ pfmul mm1, MMWORD [MMBLOCK(2,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+
+ punpcklwd mm2, mm2
+ punpcklwd mm3, mm3
+ psrad mm2, (DWORD_BIT-WORD_BIT)
+ psrad mm3, (DWORD_BIT-WORD_BIT)
+ pi2fd mm2, mm2
+ pi2fd mm3, mm3
+
+ pfmul mm2, MMWORD [MMBLOCK(4,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+ pfmul mm3, MMWORD [MMBLOCK(6,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+
+ movq mm4, mm0
+ movq mm5, mm1
+ pfsub mm0, mm2 ; mm0=tmp11
+ pfsub mm1, mm3
+ pfadd mm4, mm2 ; mm4=tmp10
+ pfadd mm5, mm3 ; mm5=tmp13
+
+ pfmul mm1, [GOTOFF(ebx,PD_1_414)]
+ pfsub mm1, mm5 ; mm1=tmp12
+
+ movq mm6, mm4
+ movq mm7, mm0
+ pfsub mm4, mm5 ; mm4=tmp3
+ pfsub mm0, mm1 ; mm0=tmp2
+ pfadd mm6, mm5 ; mm6=tmp0
+ pfadd mm7, mm1 ; mm7=tmp1
+
+ movq MMWORD [wk(1)], mm4 ; tmp3
+ movq MMWORD [wk(0)], mm0 ; tmp2
+
+ ; -- Odd part
+
+ movd mm2, dword [DWBLOCK(1,0,esi,SIZEOF_JCOEF)]
+ movd mm3, dword [DWBLOCK(3,0,esi,SIZEOF_JCOEF)]
+ movd mm5, dword [DWBLOCK(5,0,esi,SIZEOF_JCOEF)]
+ movd mm1, dword [DWBLOCK(7,0,esi,SIZEOF_JCOEF)]
+
+ punpcklwd mm2, mm2
+ punpcklwd mm3, mm3
+ psrad mm2, (DWORD_BIT-WORD_BIT)
+ psrad mm3, (DWORD_BIT-WORD_BIT)
+ pi2fd mm2, mm2
+ pi2fd mm3, mm3
+
+ pfmul mm2, MMWORD [MMBLOCK(1,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+ pfmul mm3, MMWORD [MMBLOCK(3,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+
+ punpcklwd mm5, mm5
+ punpcklwd mm1, mm1
+ psrad mm5, (DWORD_BIT-WORD_BIT)
+ psrad mm1, (DWORD_BIT-WORD_BIT)
+ pi2fd mm5, mm5
+ pi2fd mm1, mm1
+
+ pfmul mm5, MMWORD [MMBLOCK(5,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+ pfmul mm1, MMWORD [MMBLOCK(7,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
+
+ movq mm4, mm2
+ movq mm0, mm5
+ pfadd mm2, mm1 ; mm2=z11
+ pfadd mm5, mm3 ; mm5=z13
+ pfsub mm4, mm1 ; mm4=z12
+ pfsub mm0, mm3 ; mm0=z10
+
+ movq mm1, mm2
+ pfsub mm2, mm5
+ pfadd mm1, mm5 ; mm1=tmp7
+
+ pfmul mm2, [GOTOFF(ebx,PD_1_414)] ; mm2=tmp11
+
+ movq mm3, mm0
+ pfadd mm0, mm4
+ pfmul mm0, [GOTOFF(ebx,PD_1_847)] ; mm0=z5
+ pfmul mm3, [GOTOFF(ebx,PD_2_613)] ; mm3=(z10 * 2.613125930)
+ pfmul mm4, [GOTOFF(ebx,PD_1_082)] ; mm4=(z12 * 1.082392200)
+ pfsubr mm3, mm0 ; mm3=tmp12
+ pfsub mm4, mm0 ; mm4=tmp10
+
+ ; -- Final output stage
+
+ pfsub mm3, mm1 ; mm3=tmp6
+ movq mm5, mm6
+ movq mm0, mm7
+ pfadd mm6, mm1 ; mm6=data0=(00 01)
+ pfadd mm7, mm3 ; mm7=data1=(10 11)
+ pfsub mm5, mm1 ; mm5=data7=(70 71)
+ pfsub mm0, mm3 ; mm0=data6=(60 61)
+ pfsub mm2, mm3 ; mm2=tmp5
+
+ movq mm1, mm6 ; transpose coefficients
+ punpckldq mm6, mm7 ; mm6=(00 10)
+ punpckhdq mm1, mm7 ; mm1=(01 11)
+ movq mm3, mm0 ; transpose coefficients
+ punpckldq mm0, mm5 ; mm0=(60 70)
+ punpckhdq mm3, mm5 ; mm3=(61 71)
+
+ movq MMWORD [MMBLOCK(0,0,edi,SIZEOF_FAST_FLOAT)], mm6
+ movq MMWORD [MMBLOCK(1,0,edi,SIZEOF_FAST_FLOAT)], mm1
+ movq MMWORD [MMBLOCK(0,3,edi,SIZEOF_FAST_FLOAT)], mm0
+ movq MMWORD [MMBLOCK(1,3,edi,SIZEOF_FAST_FLOAT)], mm3
+
+ movq mm7, MMWORD [wk(0)] ; mm7=tmp2
+ movq mm5, MMWORD [wk(1)] ; mm5=tmp3
+
+ pfadd mm4, mm2 ; mm4=tmp4
+ movq mm6, mm7
+ movq mm1, mm5
+ pfadd mm7, mm2 ; mm7=data2=(20 21)
+ pfadd mm5, mm4 ; mm5=data4=(40 41)
+ pfsub mm6, mm2 ; mm6=data5=(50 51)
+ pfsub mm1, mm4 ; mm1=data3=(30 31)
+
+ movq mm0, mm7 ; transpose coefficients
+ punpckldq mm7, mm1 ; mm7=(20 30)
+ punpckhdq mm0, mm1 ; mm0=(21 31)
+ movq mm3, mm5 ; transpose coefficients
+ punpckldq mm5, mm6 ; mm5=(40 50)
+ punpckhdq mm3, mm6 ; mm3=(41 51)
+
+ movq MMWORD [MMBLOCK(0,1,edi,SIZEOF_FAST_FLOAT)], mm7
+ movq MMWORD [MMBLOCK(1,1,edi,SIZEOF_FAST_FLOAT)], mm0
+ movq MMWORD [MMBLOCK(0,2,edi,SIZEOF_FAST_FLOAT)], mm5
+ movq MMWORD [MMBLOCK(1,2,edi,SIZEOF_FAST_FLOAT)], mm3
+
+.nextcolumn:
+ add esi, byte 2*SIZEOF_JCOEF ; coef_block
+ add edx, byte 2*SIZEOF_FLOAT_MULT_TYPE ; quantptr
+ add edi, byte 2*DCTSIZE*SIZEOF_FAST_FLOAT ; wsptr
+ dec ecx ; ctr
+ jnz near .columnloop
+
+ ; -- Prefetch the next coefficient block
+
+ prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 0*32]
+ prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 1*32]
+ prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 2*32]
+ prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 3*32]
+
+ ; ---- Pass 2: process rows from work array, store into output array.
+
+ mov eax, [original_ebp]
+ lea esi, [workspace] ; FAST_FLOAT *wsptr
+ mov edi, JSAMPARRAY [output_buf(eax)] ; (JSAMPROW *)
+ mov eax, JDIMENSION [output_col(eax)]
+ mov ecx, DCTSIZE/2 ; ctr
+ alignx 16, 7
+.rowloop:
+
+ ; -- Even part
+
+ movq mm0, MMWORD [MMBLOCK(0,0,esi,SIZEOF_FAST_FLOAT)]
+ movq mm1, MMWORD [MMBLOCK(2,0,esi,SIZEOF_FAST_FLOAT)]
+ movq mm2, MMWORD [MMBLOCK(4,0,esi,SIZEOF_FAST_FLOAT)]
+ movq mm3, MMWORD [MMBLOCK(6,0,esi,SIZEOF_FAST_FLOAT)]
+
+ movq mm4, mm0
+ movq mm5, mm1
+ pfsub mm0, mm2 ; mm0=tmp11
+ pfsub mm1, mm3
+ pfadd mm4, mm2 ; mm4=tmp10
+ pfadd mm5, mm3 ; mm5=tmp13
+
+ pfmul mm1, [GOTOFF(ebx,PD_1_414)]
+ pfsub mm1, mm5 ; mm1=tmp12
+
+ movq mm6, mm4
+ movq mm7, mm0
+ pfsub mm4, mm5 ; mm4=tmp3
+ pfsub mm0, mm1 ; mm0=tmp2
+ pfadd mm6, mm5 ; mm6=tmp0
+ pfadd mm7, mm1 ; mm7=tmp1
+
+ movq MMWORD [wk(1)], mm4 ; tmp3
+ movq MMWORD [wk(0)], mm0 ; tmp2
+
+ ; -- Odd part
+
+ movq mm2, MMWORD [MMBLOCK(1,0,esi,SIZEOF_FAST_FLOAT)]
+ movq mm3, MMWORD [MMBLOCK(3,0,esi,SIZEOF_FAST_FLOAT)]
+ movq mm5, MMWORD [MMBLOCK(5,0,esi,SIZEOF_FAST_FLOAT)]
+ movq mm1, MMWORD [MMBLOCK(7,0,esi,SIZEOF_FAST_FLOAT)]
+
+ movq mm4, mm2
+ movq mm0, mm5
+ pfadd mm2, mm1 ; mm2=z11
+ pfadd mm5, mm3 ; mm5=z13
+ pfsub mm4, mm1 ; mm4=z12
+ pfsub mm0, mm3 ; mm0=z10
+
+ movq mm1, mm2
+ pfsub mm2, mm5
+ pfadd mm1, mm5 ; mm1=tmp7
+
+ pfmul mm2, [GOTOFF(ebx,PD_1_414)] ; mm2=tmp11
+
+ movq mm3, mm0
+ pfadd mm0, mm4
+ pfmul mm0, [GOTOFF(ebx,PD_1_847)] ; mm0=z5
+ pfmul mm3, [GOTOFF(ebx,PD_2_613)] ; mm3=(z10 * 2.613125930)
+ pfmul mm4, [GOTOFF(ebx,PD_1_082)] ; mm4=(z12 * 1.082392200)
+ pfsubr mm3, mm0 ; mm3=tmp12
+ pfsub mm4, mm0 ; mm4=tmp10
+
+ ; -- Final output stage
+
+ pfsub mm3, mm1 ; mm3=tmp6
+ movq mm5, mm6
+ movq mm0, mm7
+ pfadd mm6, mm1 ; mm6=data0=(00 10)
+ pfadd mm7, mm3 ; mm7=data1=(01 11)
+ pfsub mm5, mm1 ; mm5=data7=(07 17)
+ pfsub mm0, mm3 ; mm0=data6=(06 16)
+ pfsub mm2, mm3 ; mm2=tmp5
+
+ movq mm1, [GOTOFF(ebx,PD_RNDINT_MAGIC)] ; mm1=[PD_RNDINT_MAGIC]
+ pcmpeqd mm3, mm3
+ psrld mm3, WORD_BIT ; mm3={0xFFFF 0x0000 0xFFFF 0x0000}
+
+ pfadd mm6, mm1 ; mm6=roundint(data0/8)=(00 ** 10 **)
+ pfadd mm7, mm1 ; mm7=roundint(data1/8)=(01 ** 11 **)
+ pfadd mm0, mm1 ; mm0=roundint(data6/8)=(06 ** 16 **)
+ pfadd mm5, mm1 ; mm5=roundint(data7/8)=(07 ** 17 **)
+
+ pand mm6, mm3 ; mm6=(00 -- 10 --)
+ pslld mm7, WORD_BIT ; mm7=(-- 01 -- 11)
+ pand mm0, mm3 ; mm0=(06 -- 16 --)
+ pslld mm5, WORD_BIT ; mm5=(-- 07 -- 17)
+ por mm6, mm7 ; mm6=(00 01 10 11)
+ por mm0, mm5 ; mm0=(06 07 16 17)
+
+ movq mm1, MMWORD [wk(0)] ; mm1=tmp2
+ movq mm3, MMWORD [wk(1)] ; mm3=tmp3
+
+ pfadd mm4, mm2 ; mm4=tmp4
+ movq mm7, mm1
+ movq mm5, mm3
+ pfadd mm1, mm2 ; mm1=data2=(02 12)
+ pfadd mm3, mm4 ; mm3=data4=(04 14)
+ pfsub mm7, mm2 ; mm7=data5=(05 15)
+ pfsub mm5, mm4 ; mm5=data3=(03 13)
+
+ movq mm2, [GOTOFF(ebx,PD_RNDINT_MAGIC)] ; mm2=[PD_RNDINT_MAGIC]
+ pcmpeqd mm4, mm4
+ psrld mm4, WORD_BIT ; mm4={0xFFFF 0x0000 0xFFFF 0x0000}
+
+ pfadd mm3, mm2 ; mm3=roundint(data4/8)=(04 ** 14 **)
+ pfadd mm7, mm2 ; mm7=roundint(data5/8)=(05 ** 15 **)
+ pfadd mm1, mm2 ; mm1=roundint(data2/8)=(02 ** 12 **)
+ pfadd mm5, mm2 ; mm5=roundint(data3/8)=(03 ** 13 **)
+
+ pand mm3, mm4 ; mm3=(04 -- 14 --)
+ pslld mm7, WORD_BIT ; mm7=(-- 05 -- 15)
+ pand mm1, mm4 ; mm1=(02 -- 12 --)
+ pslld mm5, WORD_BIT ; mm5=(-- 03 -- 13)
+ por mm3, mm7 ; mm3=(04 05 14 15)
+ por mm1, mm5 ; mm1=(02 03 12 13)
+
+ movq mm2, [GOTOFF(ebx,PB_CENTERJSAMP)] ; mm2=[PB_CENTERJSAMP]
+
+ packsswb mm6, mm3 ; mm6=(00 01 10 11 04 05 14 15)
+ packsswb mm1, mm0 ; mm1=(02 03 12 13 06 07 16 17)
+ paddb mm6, mm2
+ paddb mm1, mm2
+
+ movq mm4, mm6 ; transpose coefficients(phase 2)
+ punpcklwd mm6, mm1 ; mm6=(00 01 02 03 10 11 12 13)
+ punpckhwd mm4, mm1 ; mm4=(04 05 06 07 14 15 16 17)
+
+ movq mm7, mm6 ; transpose coefficients(phase 3)
+ punpckldq mm6, mm4 ; mm6=(00 01 02 03 04 05 06 07)
+ punpckhdq mm7, mm4 ; mm7=(10 11 12 13 14 15 16 17)
+
+ pushpic ebx ; save GOT address
+
+ mov edx, JSAMPROW [edi+0*SIZEOF_JSAMPROW]
+ mov ebx, JSAMPROW [edi+1*SIZEOF_JSAMPROW]
+ movq MMWORD [edx+eax*SIZEOF_JSAMPLE], mm6
+ movq MMWORD [ebx+eax*SIZEOF_JSAMPLE], mm7
+
+ poppic ebx ; restore GOT address
+
+ add esi, byte 2*SIZEOF_FAST_FLOAT ; wsptr
+ add edi, byte 2*SIZEOF_JSAMPROW
+ dec ecx ; ctr
+ jnz near .rowloop
+
+ femms ; empty MMX/3DNow! state
+
+ pop edi
+ pop esi
+; pop edx ; need not be preserved
+; pop ecx ; need not be preserved
+ pop ebx
+ mov esp, ebp ; esp <- aligned ebp
+ pop esp ; esp <- original ebp
+ pop ebp
+ ret
+
+; For some reason, the OS X linker does not honor the request to align the
+; segment unless we do this.
+ align 32