1;
2; jidctfst.asm - fast integer IDCT (64-bit SSE2)
3;
4; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
5; Copyright (C) 2009, D. R. Commander.
6;
7; Based on the x86 SIMD extension for IJG JPEG library
8; Copyright (C) 1999-2006, MIYASAKA Masaru.
9; For conditions of distribution and use, see copyright notice in jsimdext.inc
10;
11; This file should be assembled with NASM (Netwide Assembler),
12; can *not* be assembled with Microsoft's MASM or any compatible
13; assembler (including Borland's Turbo Assembler).
14; NASM is available from http://nasm.sourceforge.net/ or
15; http://sourceforge.net/project/showfiles.php?group_id=6208
16;
17; This file contains a fast, not so accurate integer implementation of
18; the inverse DCT (Discrete Cosine Transform). The following code is
19; based directly on the IJG's original jidctfst.c; see the jidctfst.c
20; for more details.
21;
22; [TAB8]
23
24%include "jsimdext.inc"
25%include "jdct.inc"
26
27; --------------------------------------------------------------------------
28
29%define CONST_BITS      8       ; 14 is also OK.
30%define PASS1_BITS      2
31
32%if IFAST_SCALE_BITS != PASS1_BITS
33%error "'IFAST_SCALE_BITS' must be equal to 'PASS1_BITS'."
34%endif
35
36%if CONST_BITS == 8
37F_1_082 equ     277             ; FIX(1.082392200)
38F_1_414 equ     362             ; FIX(1.414213562)
39F_1_847 equ     473             ; FIX(1.847759065)
40F_2_613 equ     669             ; FIX(2.613125930)
41F_1_613 equ     (F_2_613 - 256) ; FIX(2.613125930) - FIX(1)
42%else
43; NASM cannot do compile-time arithmetic on floating-point constants.
44%define DESCALE(x,n)  (((x)+(1<<((n)-1)))>>(n))
45F_1_082 equ     DESCALE(1162209775,30-CONST_BITS)       ; FIX(1.082392200)
46F_1_414 equ     DESCALE(1518500249,30-CONST_BITS)       ; FIX(1.414213562)
47F_1_847 equ     DESCALE(1984016188,30-CONST_BITS)       ; FIX(1.847759065)
48F_2_613 equ     DESCALE(2805822602,30-CONST_BITS)       ; FIX(2.613125930)
49F_1_613 equ     (F_2_613 - (1 << CONST_BITS))   ; FIX(2.613125930) - FIX(1)
50%endif
51
52; --------------------------------------------------------------------------
53        SECTION SEG_CONST
54
55; PRE_MULTIPLY_SCALE_BITS <= 2 (to avoid overflow)
56; CONST_BITS + CONST_SHIFT + PRE_MULTIPLY_SCALE_BITS == 16 (for pmulhw)
57
58%define PRE_MULTIPLY_SCALE_BITS   2
59%define CONST_SHIFT     (16 - PRE_MULTIPLY_SCALE_BITS - CONST_BITS)
60
61        alignz  16
62        global  EXTN(jconst_idct_ifast_sse2)
63
64EXTN(jconst_idct_ifast_sse2):
65
66PW_F1414        times 8 dw  F_1_414 << CONST_SHIFT
67PW_F1847        times 8 dw  F_1_847 << CONST_SHIFT
68PW_MF1613       times 8 dw -F_1_613 << CONST_SHIFT
69PW_F1082        times 8 dw  F_1_082 << CONST_SHIFT
70PB_CENTERJSAMP  times 16 db CENTERJSAMPLE
71
72        alignz  16
73
74; --------------------------------------------------------------------------
75        SECTION SEG_TEXT
76        BITS    64
77;
78; Perform dequantization and inverse DCT on one block of coefficients.
79;
80; GLOBAL(void)
81; jsimd_idct_ifast_sse2 (void *dct_table, JCOEFPTR coef_block,
82;                       JSAMPARRAY output_buf, JDIMENSION output_col)
83;
84
85; r10 = jpeg_component_info *compptr
86; r11 = JCOEFPTR coef_block
87; r12 = JSAMPARRAY output_buf
88; r13 = JDIMENSION output_col
89
90%define original_rbp    rbp+0
91%define wk(i)           rbp-(WK_NUM-(i))*SIZEOF_XMMWORD ; xmmword wk[WK_NUM]
92%define WK_NUM          2
93
94        align   16
95        global  EXTN(jsimd_idct_ifast_sse2)
96
97EXTN(jsimd_idct_ifast_sse2):
98        push    rbp
99        mov     rax,rsp                         ; rax = original rbp
100        sub     rsp, byte 4
101        and     rsp, byte (-SIZEOF_XMMWORD)     ; align to 128 bits
102        mov     [rsp],rax
103        mov     rbp,rsp                         ; rbp = aligned rbp
104        lea     rsp, [wk(0)]
105        collect_args
106
107        ; ---- Pass 1: process columns from input.
108
109        mov     rdx, r10                ; quantptr
110        mov     rsi, r11                ; inptr
111
112%ifndef NO_ZERO_COLUMN_TEST_IFAST_SSE2
113        mov     eax, DWORD [DWBLOCK(1,0,rsi,SIZEOF_JCOEF)]
114        or      eax, DWORD [DWBLOCK(2,0,rsi,SIZEOF_JCOEF)]
115        jnz     near .columnDCT
116
117        movdqa  xmm0, XMMWORD [XMMBLOCK(1,0,rsi,SIZEOF_JCOEF)]
118        movdqa  xmm1, XMMWORD [XMMBLOCK(2,0,rsi,SIZEOF_JCOEF)]
119        por     xmm0, XMMWORD [XMMBLOCK(3,0,rsi,SIZEOF_JCOEF)]
120        por     xmm1, XMMWORD [XMMBLOCK(4,0,rsi,SIZEOF_JCOEF)]
121        por     xmm0, XMMWORD [XMMBLOCK(5,0,rsi,SIZEOF_JCOEF)]
122        por     xmm1, XMMWORD [XMMBLOCK(6,0,rsi,SIZEOF_JCOEF)]
123        por     xmm0, XMMWORD [XMMBLOCK(7,0,rsi,SIZEOF_JCOEF)]
124        por     xmm1,xmm0
125        packsswb xmm1,xmm1
126        packsswb xmm1,xmm1
127        movd    eax,xmm1
128        test    rax,rax
129        jnz     short .columnDCT
130
131        ; -- AC terms all zero
132
133        movdqa  xmm0, XMMWORD [XMMBLOCK(0,0,rsi,SIZEOF_JCOEF)]
134        pmullw  xmm0, XMMWORD [XMMBLOCK(0,0,rdx,SIZEOF_ISLOW_MULT_TYPE)]
135
136        movdqa    xmm7,xmm0             ; xmm0=in0=(00 01 02 03 04 05 06 07)
137        punpcklwd xmm0,xmm0             ; xmm0=(00 00 01 01 02 02 03 03)
138        punpckhwd xmm7,xmm7             ; xmm7=(04 04 05 05 06 06 07 07)
139
140        pshufd  xmm6,xmm0,0x00          ; xmm6=col0=(00 00 00 00 00 00 00 00)
141        pshufd  xmm2,xmm0,0x55          ; xmm2=col1=(01 01 01 01 01 01 01 01)
142        pshufd  xmm5,xmm0,0xAA          ; xmm5=col2=(02 02 02 02 02 02 02 02)
143        pshufd  xmm0,xmm0,0xFF          ; xmm0=col3=(03 03 03 03 03 03 03 03)
144        pshufd  xmm1,xmm7,0x00          ; xmm1=col4=(04 04 04 04 04 04 04 04)
145        pshufd  xmm4,xmm7,0x55          ; xmm4=col5=(05 05 05 05 05 05 05 05)
146        pshufd  xmm3,xmm7,0xAA          ; xmm3=col6=(06 06 06 06 06 06 06 06)
147        pshufd  xmm7,xmm7,0xFF          ; xmm7=col7=(07 07 07 07 07 07 07 07)
148
149        movdqa  XMMWORD [wk(0)], xmm2   ; wk(0)=col1
150        movdqa  XMMWORD [wk(1)], xmm0   ; wk(1)=col3
151        jmp     near .column_end
152%endif
153.columnDCT:
154
155        ; -- Even part
156
157        movdqa  xmm0, XMMWORD [XMMBLOCK(0,0,rsi,SIZEOF_JCOEF)]
158        movdqa  xmm1, XMMWORD [XMMBLOCK(2,0,rsi,SIZEOF_JCOEF)]
159        pmullw  xmm0, XMMWORD [XMMBLOCK(0,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
160        pmullw  xmm1, XMMWORD [XMMBLOCK(2,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
161        movdqa  xmm2, XMMWORD [XMMBLOCK(4,0,rsi,SIZEOF_JCOEF)]
162        movdqa  xmm3, XMMWORD [XMMBLOCK(6,0,rsi,SIZEOF_JCOEF)]
163        pmullw  xmm2, XMMWORD [XMMBLOCK(4,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
164        pmullw  xmm3, XMMWORD [XMMBLOCK(6,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
165
166        movdqa  xmm4,xmm0
167        movdqa  xmm5,xmm1
168        psubw   xmm0,xmm2               ; xmm0=tmp11
169        psubw   xmm1,xmm3
170        paddw   xmm4,xmm2               ; xmm4=tmp10
171        paddw   xmm5,xmm3               ; xmm5=tmp13
172
173        psllw   xmm1,PRE_MULTIPLY_SCALE_BITS
174        pmulhw  xmm1,[rel PW_F1414]
175        psubw   xmm1,xmm5               ; xmm1=tmp12
176
177        movdqa  xmm6,xmm4
178        movdqa  xmm7,xmm0
179        psubw   xmm4,xmm5               ; xmm4=tmp3
180        psubw   xmm0,xmm1               ; xmm0=tmp2
181        paddw   xmm6,xmm5               ; xmm6=tmp0
182        paddw   xmm7,xmm1               ; xmm7=tmp1
183
184        movdqa  XMMWORD [wk(1)], xmm4   ; wk(1)=tmp3
185        movdqa  XMMWORD [wk(0)], xmm0   ; wk(0)=tmp2
186
187        ; -- Odd part
188
189        movdqa  xmm2, XMMWORD [XMMBLOCK(1,0,rsi,SIZEOF_JCOEF)]
190        movdqa  xmm3, XMMWORD [XMMBLOCK(3,0,rsi,SIZEOF_JCOEF)]
191        pmullw  xmm2, XMMWORD [XMMBLOCK(1,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
192        pmullw  xmm3, XMMWORD [XMMBLOCK(3,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
193        movdqa  xmm5, XMMWORD [XMMBLOCK(5,0,rsi,SIZEOF_JCOEF)]
194        movdqa  xmm1, XMMWORD [XMMBLOCK(7,0,rsi,SIZEOF_JCOEF)]
195        pmullw  xmm5, XMMWORD [XMMBLOCK(5,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
196        pmullw  xmm1, XMMWORD [XMMBLOCK(7,0,rdx,SIZEOF_IFAST_MULT_TYPE)]
197
198        movdqa  xmm4,xmm2
199        movdqa  xmm0,xmm5
200        psubw   xmm2,xmm1               ; xmm2=z12
201        psubw   xmm5,xmm3               ; xmm5=z10
202        paddw   xmm4,xmm1               ; xmm4=z11
203        paddw   xmm0,xmm3               ; xmm0=z13
204
205        movdqa  xmm1,xmm5               ; xmm1=z10(unscaled)
206        psllw   xmm2,PRE_MULTIPLY_SCALE_BITS
207        psllw   xmm5,PRE_MULTIPLY_SCALE_BITS
208
209        movdqa  xmm3,xmm4
210        psubw   xmm4,xmm0
211        paddw   xmm3,xmm0               ; xmm3=tmp7
212
213        psllw   xmm4,PRE_MULTIPLY_SCALE_BITS
214        pmulhw  xmm4,[rel PW_F1414]     ; xmm4=tmp11
215
216        ; To avoid overflow...
217        ;
218        ; (Original)
219        ; tmp12 = -2.613125930 * z10 + z5;
220        ;
221        ; (This implementation)
222        ; tmp12 = (-1.613125930 - 1) * z10 + z5;
223        ;       = -1.613125930 * z10 - z10 + z5;
224
225        movdqa  xmm0,xmm5
226        paddw   xmm5,xmm2
227        pmulhw  xmm5,[rel PW_F1847]     ; xmm5=z5
228        pmulhw  xmm0,[rel PW_MF1613]
229        pmulhw  xmm2,[rel PW_F1082]
230        psubw   xmm0,xmm1
231        psubw   xmm2,xmm5               ; xmm2=tmp10
232        paddw   xmm0,xmm5               ; xmm0=tmp12
233
234        ; -- Final output stage
235
236        psubw   xmm0,xmm3               ; xmm0=tmp6
237        movdqa  xmm1,xmm6
238        movdqa  xmm5,xmm7
239        paddw   xmm6,xmm3               ; xmm6=data0=(00 01 02 03 04 05 06 07)
240        paddw   xmm7,xmm0               ; xmm7=data1=(10 11 12 13 14 15 16 17)
241        psubw   xmm1,xmm3               ; xmm1=data7=(70 71 72 73 74 75 76 77)
242        psubw   xmm5,xmm0               ; xmm5=data6=(60 61 62 63 64 65 66 67)
243        psubw   xmm4,xmm0               ; xmm4=tmp5
244
245        movdqa    xmm3,xmm6             ; transpose coefficients(phase 1)
246        punpcklwd xmm6,xmm7             ; xmm6=(00 10 01 11 02 12 03 13)
247        punpckhwd xmm3,xmm7             ; xmm3=(04 14 05 15 06 16 07 17)
248        movdqa    xmm0,xmm5             ; transpose coefficients(phase 1)
249        punpcklwd xmm5,xmm1             ; xmm5=(60 70 61 71 62 72 63 73)
250        punpckhwd xmm0,xmm1             ; xmm0=(64 74 65 75 66 76 67 77)
251
252        movdqa  xmm7, XMMWORD [wk(0)]   ; xmm7=tmp2
253        movdqa  xmm1, XMMWORD [wk(1)]   ; xmm1=tmp3
254
255        movdqa  XMMWORD [wk(0)], xmm5   ; wk(0)=(60 70 61 71 62 72 63 73)
256        movdqa  XMMWORD [wk(1)], xmm0   ; wk(1)=(64 74 65 75 66 76 67 77)
257
258        paddw   xmm2,xmm4               ; xmm2=tmp4
259        movdqa  xmm5,xmm7
260        movdqa  xmm0,xmm1
261        paddw   xmm7,xmm4               ; xmm7=data2=(20 21 22 23 24 25 26 27)
262        paddw   xmm1,xmm2               ; xmm1=data4=(40 41 42 43 44 45 46 47)
263        psubw   xmm5,xmm4               ; xmm5=data5=(50 51 52 53 54 55 56 57)
264        psubw   xmm0,xmm2               ; xmm0=data3=(30 31 32 33 34 35 36 37)
265
266        movdqa    xmm4,xmm7             ; transpose coefficients(phase 1)
267        punpcklwd xmm7,xmm0             ; xmm7=(20 30 21 31 22 32 23 33)
268        punpckhwd xmm4,xmm0             ; xmm4=(24 34 25 35 26 36 27 37)
269        movdqa    xmm2,xmm1             ; transpose coefficients(phase 1)
270        punpcklwd xmm1,xmm5             ; xmm1=(40 50 41 51 42 52 43 53)
271        punpckhwd xmm2,xmm5             ; xmm2=(44 54 45 55 46 56 47 57)
272
273        movdqa    xmm0,xmm3             ; transpose coefficients(phase 2)
274        punpckldq xmm3,xmm4             ; xmm3=(04 14 24 34 05 15 25 35)
275        punpckhdq xmm0,xmm4             ; xmm0=(06 16 26 36 07 17 27 37)
276        movdqa    xmm5,xmm6             ; transpose coefficients(phase 2)
277        punpckldq xmm6,xmm7             ; xmm6=(00 10 20 30 01 11 21 31)
278        punpckhdq xmm5,xmm7             ; xmm5=(02 12 22 32 03 13 23 33)
279
280        movdqa  xmm4, XMMWORD [wk(0)]   ; xmm4=(60 70 61 71 62 72 63 73)
281        movdqa  xmm7, XMMWORD [wk(1)]   ; xmm7=(64 74 65 75 66 76 67 77)
282
283        movdqa  XMMWORD [wk(0)], xmm3   ; wk(0)=(04 14 24 34 05 15 25 35)
284        movdqa  XMMWORD [wk(1)], xmm0   ; wk(1)=(06 16 26 36 07 17 27 37)
285
286        movdqa    xmm3,xmm1             ; transpose coefficients(phase 2)
287        punpckldq xmm1,xmm4             ; xmm1=(40 50 60 70 41 51 61 71)
288        punpckhdq xmm3,xmm4             ; xmm3=(42 52 62 72 43 53 63 73)
289        movdqa    xmm0,xmm2             ; transpose coefficients(phase 2)
290        punpckldq xmm2,xmm7             ; xmm2=(44 54 64 74 45 55 65 75)
291        punpckhdq xmm0,xmm7             ; xmm0=(46 56 66 76 47 57 67 77)
292
293        movdqa     xmm4,xmm6            ; transpose coefficients(phase 3)
294        punpcklqdq xmm6,xmm1            ; xmm6=col0=(00 10 20 30 40 50 60 70)
295        punpckhqdq xmm4,xmm1            ; xmm4=col1=(01 11 21 31 41 51 61 71)
296        movdqa     xmm7,xmm5            ; transpose coefficients(phase 3)
297        punpcklqdq xmm5,xmm3            ; xmm5=col2=(02 12 22 32 42 52 62 72)
298        punpckhqdq xmm7,xmm3            ; xmm7=col3=(03 13 23 33 43 53 63 73)
299
300        movdqa  xmm1, XMMWORD [wk(0)]   ; xmm1=(04 14 24 34 05 15 25 35)
301        movdqa  xmm3, XMMWORD [wk(1)]   ; xmm3=(06 16 26 36 07 17 27 37)
302
303        movdqa  XMMWORD [wk(0)], xmm4   ; wk(0)=col1
304        movdqa  XMMWORD [wk(1)], xmm7   ; wk(1)=col3
305
306        movdqa     xmm4,xmm1            ; transpose coefficients(phase 3)
307        punpcklqdq xmm1,xmm2            ; xmm1=col4=(04 14 24 34 44 54 64 74)
308        punpckhqdq xmm4,xmm2            ; xmm4=col5=(05 15 25 35 45 55 65 75)
309        movdqa     xmm7,xmm3            ; transpose coefficients(phase 3)
310        punpcklqdq xmm3,xmm0            ; xmm3=col6=(06 16 26 36 46 56 66 76)
311        punpckhqdq xmm7,xmm0            ; xmm7=col7=(07 17 27 37 47 57 67 77)
312.column_end:
313
314        ; -- Prefetch the next coefficient block
315
316        prefetchnta [rsi + DCTSIZE2*SIZEOF_JCOEF + 0*32]
317        prefetchnta [rsi + DCTSIZE2*SIZEOF_JCOEF + 1*32]
318        prefetchnta [rsi + DCTSIZE2*SIZEOF_JCOEF + 2*32]
319        prefetchnta [rsi + DCTSIZE2*SIZEOF_JCOEF + 3*32]
320
321        ; ---- Pass 2: process rows from work array, store into output array.
322
323        mov     rax, [original_rbp]
324        mov     rdi, r12        ; (JSAMPROW *)
325        mov     eax, r13d
326
327        ; -- Even part
328
329        ; xmm6=col0, xmm5=col2, xmm1=col4, xmm3=col6
330
331        movdqa  xmm2,xmm6
332        movdqa  xmm0,xmm5
333        psubw   xmm6,xmm1               ; xmm6=tmp11
334        psubw   xmm5,xmm3
335        paddw   xmm2,xmm1               ; xmm2=tmp10
336        paddw   xmm0,xmm3               ; xmm0=tmp13
337
338        psllw   xmm5,PRE_MULTIPLY_SCALE_BITS
339        pmulhw  xmm5,[rel PW_F1414]
340        psubw   xmm5,xmm0               ; xmm5=tmp12
341
342        movdqa  xmm1,xmm2
343        movdqa  xmm3,xmm6
344        psubw   xmm2,xmm0               ; xmm2=tmp3
345        psubw   xmm6,xmm5               ; xmm6=tmp2
346        paddw   xmm1,xmm0               ; xmm1=tmp0
347        paddw   xmm3,xmm5               ; xmm3=tmp1
348
349        movdqa  xmm0, XMMWORD [wk(0)]   ; xmm0=col1
350        movdqa  xmm5, XMMWORD [wk(1)]   ; xmm5=col3
351
352        movdqa  XMMWORD [wk(0)], xmm2   ; wk(0)=tmp3
353        movdqa  XMMWORD [wk(1)], xmm6   ; wk(1)=tmp2
354
355        ; -- Odd part
356
357        ; xmm0=col1, xmm5=col3, xmm4=col5, xmm7=col7
358
359        movdqa  xmm2,xmm0
360        movdqa  xmm6,xmm4
361        psubw   xmm0,xmm7               ; xmm0=z12
362        psubw   xmm4,xmm5               ; xmm4=z10
363        paddw   xmm2,xmm7               ; xmm2=z11
364        paddw   xmm6,xmm5               ; xmm6=z13
365
366        movdqa  xmm7,xmm4               ; xmm7=z10(unscaled)
367        psllw   xmm0,PRE_MULTIPLY_SCALE_BITS
368        psllw   xmm4,PRE_MULTIPLY_SCALE_BITS
369
370        movdqa  xmm5,xmm2
371        psubw   xmm2,xmm6
372        paddw   xmm5,xmm6               ; xmm5=tmp7
373
374        psllw   xmm2,PRE_MULTIPLY_SCALE_BITS
375        pmulhw  xmm2,[rel PW_F1414]     ; xmm2=tmp11
376
377        ; To avoid overflow...
378        ;
379        ; (Original)
380        ; tmp12 = -2.613125930 * z10 + z5;
381        ;
382        ; (This implementation)
383        ; tmp12 = (-1.613125930 - 1) * z10 + z5;
384        ;       = -1.613125930 * z10 - z10 + z5;
385
386        movdqa  xmm6,xmm4
387        paddw   xmm4,xmm0
388        pmulhw  xmm4,[rel PW_F1847]     ; xmm4=z5
389        pmulhw  xmm6,[rel PW_MF1613]
390        pmulhw  xmm0,[rel PW_F1082]
391        psubw   xmm6,xmm7
392        psubw   xmm0,xmm4               ; xmm0=tmp10
393        paddw   xmm6,xmm4               ; xmm6=tmp12
394
395        ; -- Final output stage
396
397        psubw   xmm6,xmm5               ; xmm6=tmp6
398        movdqa  xmm7,xmm1
399        movdqa  xmm4,xmm3
400        paddw   xmm1,xmm5               ; xmm1=data0=(00 10 20 30 40 50 60 70)
401        paddw   xmm3,xmm6               ; xmm3=data1=(01 11 21 31 41 51 61 71)
402        psraw   xmm1,(PASS1_BITS+3)     ; descale
403        psraw   xmm3,(PASS1_BITS+3)     ; descale
404        psubw   xmm7,xmm5               ; xmm7=data7=(07 17 27 37 47 57 67 77)
405        psubw   xmm4,xmm6               ; xmm4=data6=(06 16 26 36 46 56 66 76)
406        psraw   xmm7,(PASS1_BITS+3)     ; descale
407        psraw   xmm4,(PASS1_BITS+3)     ; descale
408        psubw   xmm2,xmm6               ; xmm2=tmp5
409
410        packsswb  xmm1,xmm4     ; xmm1=(00 10 20 30 40 50 60 70 06 16 26 36 46 56 66 76)
411        packsswb  xmm3,xmm7     ; xmm3=(01 11 21 31 41 51 61 71 07 17 27 37 47 57 67 77)
412
413        movdqa  xmm5, XMMWORD [wk(1)]   ; xmm5=tmp2
414        movdqa  xmm6, XMMWORD [wk(0)]   ; xmm6=tmp3
415
416        paddw   xmm0,xmm2               ; xmm0=tmp4
417        movdqa  xmm4,xmm5
418        movdqa  xmm7,xmm6
419        paddw   xmm5,xmm2               ; xmm5=data2=(02 12 22 32 42 52 62 72)
420        paddw   xmm6,xmm0               ; xmm6=data4=(04 14 24 34 44 54 64 74)
421        psraw   xmm5,(PASS1_BITS+3)     ; descale
422        psraw   xmm6,(PASS1_BITS+3)     ; descale
423        psubw   xmm4,xmm2               ; xmm4=data5=(05 15 25 35 45 55 65 75)
424        psubw   xmm7,xmm0               ; xmm7=data3=(03 13 23 33 43 53 63 73)
425        psraw   xmm4,(PASS1_BITS+3)     ; descale
426        psraw   xmm7,(PASS1_BITS+3)     ; descale
427
428        movdqa    xmm2,[rel PB_CENTERJSAMP]     ; xmm2=[rel PB_CENTERJSAMP]
429
430        packsswb  xmm5,xmm6     ; xmm5=(02 12 22 32 42 52 62 72 04 14 24 34 44 54 64 74)
431        packsswb  xmm7,xmm4     ; xmm7=(03 13 23 33 43 53 63 73 05 15 25 35 45 55 65 75)
432
433        paddb     xmm1,xmm2
434        paddb     xmm3,xmm2
435        paddb     xmm5,xmm2
436        paddb     xmm7,xmm2
437
438        movdqa    xmm0,xmm1     ; transpose coefficients(phase 1)
439        punpcklbw xmm1,xmm3     ; xmm1=(00 01 10 11 20 21 30 31 40 41 50 51 60 61 70 71)
440        punpckhbw xmm0,xmm3     ; xmm0=(06 07 16 17 26 27 36 37 46 47 56 57 66 67 76 77)
441        movdqa    xmm6,xmm5     ; transpose coefficients(phase 1)
442        punpcklbw xmm5,xmm7     ; xmm5=(02 03 12 13 22 23 32 33 42 43 52 53 62 63 72 73)
443        punpckhbw xmm6,xmm7     ; xmm6=(04 05 14 15 24 25 34 35 44 45 54 55 64 65 74 75)
444
445        movdqa    xmm4,xmm1     ; transpose coefficients(phase 2)
446        punpcklwd xmm1,xmm5     ; xmm1=(00 01 02 03 10 11 12 13 20 21 22 23 30 31 32 33)
447        punpckhwd xmm4,xmm5     ; xmm4=(40 41 42 43 50 51 52 53 60 61 62 63 70 71 72 73)
448        movdqa    xmm2,xmm6     ; transpose coefficients(phase 2)
449        punpcklwd xmm6,xmm0     ; xmm6=(04 05 06 07 14 15 16 17 24 25 26 27 34 35 36 37)
450        punpckhwd xmm2,xmm0     ; xmm2=(44 45 46 47 54 55 56 57 64 65 66 67 74 75 76 77)
451
452        movdqa    xmm3,xmm1     ; transpose coefficients(phase 3)
453        punpckldq xmm1,xmm6     ; xmm1=(00 01 02 03 04 05 06 07 10 11 12 13 14 15 16 17)
454        punpckhdq xmm3,xmm6     ; xmm3=(20 21 22 23 24 25 26 27 30 31 32 33 34 35 36 37)
455        movdqa    xmm7,xmm4     ; transpose coefficients(phase 3)
456        punpckldq xmm4,xmm2     ; xmm4=(40 41 42 43 44 45 46 47 50 51 52 53 54 55 56 57)
457        punpckhdq xmm7,xmm2     ; xmm7=(60 61 62 63 64 65 66 67 70 71 72 73 74 75 76 77)
458
459        pshufd  xmm5,xmm1,0x4E  ; xmm5=(10 11 12 13 14 15 16 17 00 01 02 03 04 05 06 07)
460        pshufd  xmm0,xmm3,0x4E  ; xmm0=(30 31 32 33 34 35 36 37 20 21 22 23 24 25 26 27)
461        pshufd  xmm6,xmm4,0x4E  ; xmm6=(50 51 52 53 54 55 56 57 40 41 42 43 44 45 46 47)
462        pshufd  xmm2,xmm7,0x4E  ; xmm2=(70 71 72 73 74 75 76 77 60 61 62 63 64 65 66 67)
463
464        mov     rdx, JSAMPROW [rdi+0*SIZEOF_JSAMPROW]
465        mov     rsi, JSAMPROW [rdi+2*SIZEOF_JSAMPROW]
466        movq    XMM_MMWORD [rdx+rax*SIZEOF_JSAMPLE], xmm1
467        movq    XMM_MMWORD [rsi+rax*SIZEOF_JSAMPLE], xmm3
468        mov     rdx, JSAMPROW [rdi+4*SIZEOF_JSAMPROW]
469        mov     rsi, JSAMPROW [rdi+6*SIZEOF_JSAMPROW]
470        movq    XMM_MMWORD [rdx+rax*SIZEOF_JSAMPLE], xmm4
471        movq    XMM_MMWORD [rsi+rax*SIZEOF_JSAMPLE], xmm7
472
473        mov     rdx, JSAMPROW [rdi+1*SIZEOF_JSAMPROW]
474        mov     rsi, JSAMPROW [rdi+3*SIZEOF_JSAMPROW]
475        movq    XMM_MMWORD [rdx+rax*SIZEOF_JSAMPLE], xmm5
476        movq    XMM_MMWORD [rsi+rax*SIZEOF_JSAMPLE], xmm0
477        mov     rdx, JSAMPROW [rdi+5*SIZEOF_JSAMPROW]
478        mov     rsi, JSAMPROW [rdi+7*SIZEOF_JSAMPROW]
479        movq    XMM_MMWORD [rdx+rax*SIZEOF_JSAMPLE], xmm6
480        movq    XMM_MMWORD [rsi+rax*SIZEOF_JSAMPLE], xmm2
481
482        uncollect_args
483        mov     rsp,rbp         ; rsp <- aligned rbp
484        pop     rsp             ; rsp <- original rbp
485        pop     rbp
486        ret
487        ret
488
489; For some reason, the OS X linker does not honor the request to align the
490; segment unless we do this.
491        align   16
492