xref: /aosp_15_r20/external/libjpeg-turbo/simd/x86_64/jchuff-sse2.asm (revision dfc6aa5c1cfd4bc4e2018dc74aa96e29ee49c6da)
1;
2; jchuff-sse2.asm - Huffman entropy encoding (64-bit SSE2)
3;
4; Copyright (C) 2009-2011, 2014-2016, 2019, 2021, D. R. Commander.
5; Copyright (C) 2015, Matthieu Darbois.
6; Copyright (C) 2018, Matthias Räncker.
7;
8; Based on the x86 SIMD extension for IJG JPEG library
9; Copyright (C) 1999-2006, MIYASAKA Masaru.
10; For conditions of distribution and use, see copyright notice in jsimdext.inc
11;
12; This file should be assembled with NASM (Netwide Assembler),
13; can *not* be assembled with Microsoft's MASM or any compatible
14; assembler (including Borland's Turbo Assembler).
15; NASM is available from http://nasm.sourceforge.net/ or
16; http://sourceforge.net/project/showfiles.php?group_id=6208
17;
18; This file contains an SSE2 implementation for Huffman coding of one block.
19; The following code is based on jchuff.c; see jchuff.c for more details.
20
21%include "jsimdext.inc"
22
23struc working_state
24.next_output_byte:   resp 1     ; => next byte to write in buffer
25.free_in_buffer:     resp 1     ; # of byte spaces remaining in buffer
26.cur.put_buffer.simd resq 1     ; current bit accumulation buffer
27.cur.free_bits       resd 1     ; # of bits available in it
28.cur.last_dc_val     resd 4     ; last DC coef for each component
29.cinfo:              resp 1     ; dump_buffer needs access to this
30endstruc
31
32struc c_derived_tbl
33.ehufco:             resd 256   ; code for each symbol
34.ehufsi:             resb 256   ; length of code for each symbol
35; If no code has been allocated for a symbol S, ehufsi[S] contains 0
36endstruc
37
38; --------------------------------------------------------------------------
39    SECTION     SEG_CONST
40
41    alignz      32
42    GLOBAL_DATA(jconst_huff_encode_one_block)
43
44EXTN(jconst_huff_encode_one_block):
45
46jpeg_mask_bits dd 0x0000, 0x0001, 0x0003, 0x0007
47               dd 0x000f, 0x001f, 0x003f, 0x007f
48               dd 0x00ff, 0x01ff, 0x03ff, 0x07ff
49               dd 0x0fff, 0x1fff, 0x3fff, 0x7fff
50
51    alignz      32
52
53times 1 << 14 db 15
54times 1 << 13 db 14
55times 1 << 12 db 13
56times 1 << 11 db 12
57times 1 << 10 db 11
58times 1 <<  9 db 10
59times 1 <<  8 db  9
60times 1 <<  7 db  8
61times 1 <<  6 db  7
62times 1 <<  5 db  6
63times 1 <<  4 db  5
64times 1 <<  3 db  4
65times 1 <<  2 db  3
66times 1 <<  1 db  2
67times 1 <<  0 db  1
68times 1       db  0
69jpeg_nbits_table:
70times 1       db  0
71times 1 <<  0 db  1
72times 1 <<  1 db  2
73times 1 <<  2 db  3
74times 1 <<  3 db  4
75times 1 <<  4 db  5
76times 1 <<  5 db  6
77times 1 <<  6 db  7
78times 1 <<  7 db  8
79times 1 <<  8 db  9
80times 1 <<  9 db 10
81times 1 << 10 db 11
82times 1 << 11 db 12
83times 1 << 12 db 13
84times 1 << 13 db 14
85times 1 << 14 db 15
86times 1 << 15 db 16
87
88    alignz      32
89
90%define NBITS(x)      nbits_base + x
91%define MASK_BITS(x)  NBITS((x) * 4) + (jpeg_mask_bits - jpeg_nbits_table)
92
93; --------------------------------------------------------------------------
94    SECTION     SEG_TEXT
95    BITS        64
96
97; Shorthand used to describe SIMD operations:
98; wN:  xmmN treated as eight signed 16-bit values
99; wN[i]:  perform the same operation on all eight signed 16-bit values, i=0..7
100; bN:  xmmN treated as 16 unsigned 8-bit values
101; bN[i]:  perform the same operation on all 16 unsigned 8-bit values, i=0..15
102; Contents of SIMD registers are shown in memory order.
103
104; Fill the bit buffer to capacity with the leading bits from code, then output
105; the bit buffer and put the remaining bits from code into the bit buffer.
106;
107; Usage:
108; code - contains the bits to shift into the bit buffer (LSB-aligned)
109; %1 - the label to which to jump when the macro completes
110; %2 (optional) - extra instructions to execute after nbits has been set
111;
112; Upon completion, free_bits will be set to the number of remaining bits from
113; code, and put_buffer will contain those remaining bits.  temp and code will
114; be clobbered.
115;
116; This macro encodes any 0xFF bytes as 0xFF 0x00, as does the EMIT_BYTE()
117; macro in jchuff.c.
118
119%macro EMIT_QWORD 1-2
120    add         nbitsb, free_bitsb      ; nbits += free_bits;
121    neg         free_bitsb              ; free_bits = -free_bits;
122    mov         tempd, code             ; temp = code;
123    shl         put_buffer, nbitsb      ; put_buffer <<= nbits;
124    mov         nbitsb, free_bitsb      ; nbits = free_bits;
125    neg         free_bitsb              ; free_bits = -free_bits;
126    shr         tempd, nbitsb           ; temp >>= nbits;
127    or          tempq, put_buffer       ; temp |= put_buffer;
128    movq        xmm0, tempq             ; xmm0.u64 = { temp, 0 };
129    bswap       tempq                   ; temp = htonl(temp);
130    mov         put_buffer, codeq       ; put_buffer = code;
131    pcmpeqb     xmm0, xmm1              ; b0[i] = (b0[i] == 0xFF ? 0xFF : 0);
132    %2
133    pmovmskb    code, xmm0              ; code = 0;  code |= ((b0[i] >> 7) << i);
134    mov         qword [buffer], tempq   ; memcpy(buffer, &temp, 8);
135                                        ; (speculative; will be overwritten if
136                                        ; code contains any 0xFF bytes)
137    add         free_bitsb, 64          ; free_bits += 64;
138    add         bufferp, 8              ; buffer += 8;
139    test        code, code              ; if (code == 0)  /* No 0xFF bytes */
140    jz          %1                      ;   return;
141    ; Execute the equivalent of the EMIT_BYTE() macro in jchuff.c for all 8
142    ; bytes in the qword.
143    cmp         tempb, 0xFF             ; Set CF if temp[0] < 0xFF
144    mov         byte [buffer-7], 0      ; buffer[-7] = 0;
145    sbb         bufferp, 6              ; buffer -= (6 + (temp[0] < 0xFF ? 1 : 0));
146    mov         byte [buffer], temph    ; buffer[0] = temp[1];
147    cmp         temph, 0xFF             ; Set CF if temp[1] < 0xFF
148    mov         byte [buffer+1], 0      ; buffer[1] = 0;
149    sbb         bufferp, -2             ; buffer -= (-2 + (temp[1] < 0xFF ? 1 : 0));
150    shr         tempq, 16               ; temp >>= 16;
151    mov         byte [buffer], tempb    ; buffer[0] = temp[0];
152    cmp         tempb, 0xFF             ; Set CF if temp[0] < 0xFF
153    mov         byte [buffer+1], 0      ; buffer[1] = 0;
154    sbb         bufferp, -2             ; buffer -= (-2 + (temp[0] < 0xFF ? 1 : 0));
155    mov         byte [buffer], temph    ; buffer[0] = temp[1];
156    cmp         temph, 0xFF             ; Set CF if temp[1] < 0xFF
157    mov         byte [buffer+1], 0      ; buffer[1] = 0;
158    sbb         bufferp, -2             ; buffer -= (-2 + (temp[1] < 0xFF ? 1 : 0));
159    shr         tempq, 16               ; temp >>= 16;
160    mov         byte [buffer], tempb    ; buffer[0] = temp[0];
161    cmp         tempb, 0xFF             ; Set CF if temp[0] < 0xFF
162    mov         byte [buffer+1], 0      ; buffer[1] = 0;
163    sbb         bufferp, -2             ; buffer -= (-2 + (temp[0] < 0xFF ? 1 : 0));
164    mov         byte [buffer], temph    ; buffer[0] = temp[1];
165    cmp         temph, 0xFF             ; Set CF if temp[1] < 0xFF
166    mov         byte [buffer+1], 0      ; buffer[1] = 0;
167    sbb         bufferp, -2             ; buffer -= (-2 + (temp[1] < 0xFF ? 1 : 0));
168    shr         tempd, 16               ; temp >>= 16;
169    mov         byte [buffer], tempb    ; buffer[0] = temp[0];
170    cmp         tempb, 0xFF             ; Set CF if temp[0] < 0xFF
171    mov         byte [buffer+1], 0      ; buffer[1] = 0;
172    sbb         bufferp, -2             ; buffer -= (-2 + (temp[0] < 0xFF ? 1 : 0));
173    mov         byte [buffer], temph    ; buffer[0] = temp[1];
174    cmp         temph, 0xFF             ; Set CF if temp[1] < 0xFF
175    mov         byte [buffer+1], 0      ; buffer[1] = 0;
176    sbb         bufferp, -2             ; buffer -= (-2 + (temp[1] < 0xFF ? 1 : 0));
177    jmp         %1                      ; return;
178%endmacro
179
180;
181; Encode a single block's worth of coefficients.
182;
183; GLOBAL(JOCTET *)
184; jsimd_huff_encode_one_block_sse2(working_state *state, JOCTET *buffer,
185;                                  JCOEFPTR block, int last_dc_val,
186;                                  c_derived_tbl *dctbl, c_derived_tbl *actbl)
187;
188; NOTES:
189; When shuffling data, we try to avoid pinsrw as much as possible, since it is
190; slow on many CPUs.  Its reciprocal throughput (issue latency) is 1 even on
191; modern CPUs, so chains of pinsrw instructions (even with different outputs)
192; can limit performance.  pinsrw is a VectorPath instruction on AMD K8 and
193; requires 2 µops (with memory operand) on Intel.  In either case, only one
194; pinsrw instruction can be decoded per cycle (and nothing else if they are
195; back-to-back), so out-of-order execution cannot be used to work around long
196; pinsrw chains (though for Sandy Bridge and later, this may be less of a
197; problem if the code runs from the µop cache.)
198;
199; We use tzcnt instead of bsf without checking for support.  The instruction is
200; executed as bsf on CPUs that don't support tzcnt (encoding is equivalent to
201; rep bsf.)  The destination (first) operand of bsf (and tzcnt on some CPUs) is
202; an input dependency (although the behavior is not formally defined, Intel
203; CPUs usually leave the destination unmodified if the source is zero.)  This
204; can prevent out-of-order execution, so we clear the destination before
205; invoking tzcnt.
206;
207; Initial register allocation
208; rax - buffer
209; rbx - temp
210; rcx - nbits
211; rdx - block --> free_bits
212; rsi - nbits_base
213; rdi - t
214; rbp - code
215; r8  - dctbl --> code_temp
216; r9  - actbl
217; r10 - state
218; r11 - index
219; r12 - put_buffer
220
221%define buffer       rax
222%ifdef WIN64
223%define bufferp      rax
224%else
225%define bufferp      raxp
226%endif
227%define tempq        rbx
228%define tempd        ebx
229%define tempb        bl
230%define temph        bh
231%define nbitsq       rcx
232%define nbits        ecx
233%define nbitsb       cl
234%define block        rdx
235%define nbits_base   rsi
236%define t            rdi
237%define td           edi
238%define codeq        rbp
239%define code         ebp
240%define dctbl        r8
241%define actbl        r9
242%define state        r10
243%define index        r11
244%define indexd       r11d
245%define put_buffer   r12
246%define put_bufferd  r12d
247
248; Step 1: Re-arrange input data according to jpeg_natural_order
249; xx 01 02 03 04 05 06 07      xx 01 08 16 09 02 03 10
250; 08 09 10 11 12 13 14 15      17 24 32 25 18 11 04 05
251; 16 17 18 19 20 21 22 23      12 19 26 33 40 48 41 34
252; 24 25 26 27 28 29 30 31 ==>  27 20 13 06 07 14 21 28
253; 32 33 34 35 36 37 38 39      35 42 49 56 57 50 43 36
254; 40 41 42 43 44 45 46 47      29 22 15 23 30 37 44 51
255; 48 49 50 51 52 53 54 55      58 59 52 45 38 31 39 46
256; 56 57 58 59 60 61 62 63      53 60 61 54 47 55 62 63
257
258    align       32
259    GLOBAL_FUNCTION(jsimd_huff_encode_one_block_sse2)
260
261EXTN(jsimd_huff_encode_one_block_sse2):
262
263%ifdef WIN64
264
265; rcx = working_state *state
266; rdx = JOCTET *buffer
267; r8 = JCOEFPTR block
268; r9 = int last_dc_val
269; [rax+48] = c_derived_tbl *dctbl
270; [rax+56] = c_derived_tbl *actbl
271
272                                                          ;X: X = code stream
273    mov         buffer, rdx
274    mov         block, r8
275    movups      xmm3, XMMWORD [block + 0 * SIZEOF_WORD]   ;D: w3 = xx 01 02 03 04 05 06 07
276    push        rbx
277    push        rbp
278    movdqa      xmm0, xmm3                                ;A: w0 = xx 01 02 03 04 05 06 07
279    push        rsi
280    push        rdi
281    push        r12
282    movups      xmm1, XMMWORD [block + 8 * SIZEOF_WORD]   ;B: w1 = 08 09 10 11 12 13 14 15
283    mov         state, rcx
284    movsx       code, word [block]                        ;Z:     code = block[0];
285    pxor        xmm4, xmm4                                ;A: w4[i] = 0;
286    sub         code, r9d                                 ;Z:     code -= last_dc_val;
287    mov         dctbl, POINTER [rsp+6*8+4*8]
288    mov         actbl, POINTER [rsp+6*8+5*8]
289    punpckldq   xmm0, xmm1                                ;A: w0 = xx 01 08 09 02 03 10 11
290    lea         nbits_base, [rel jpeg_nbits_table]
291    add         rsp, -DCTSIZE2 * SIZEOF_WORD
292    mov         t, rsp
293
294%else
295
296; rdi = working_state *state
297; rsi = JOCTET *buffer
298; rdx = JCOEFPTR block
299; rcx = int last_dc_val
300; r8 = c_derived_tbl *dctbl
301; r9 = c_derived_tbl *actbl
302
303                                                          ;X: X = code stream
304    movups      xmm3, XMMWORD [block + 0 * SIZEOF_WORD]   ;D: w3 = xx 01 02 03 04 05 06 07
305    push        rbx
306    push        rbp
307    movdqa      xmm0, xmm3                                ;A: w0 = xx 01 02 03 04 05 06 07
308    push        r12
309    mov         state, rdi
310    mov         buffer, rsi
311    movups      xmm1, XMMWORD [block + 8 * SIZEOF_WORD]   ;B: w1 = 08 09 10 11 12 13 14 15
312    movsx       codeq, word [block]                       ;Z:     code = block[0];
313    lea         nbits_base, [rel jpeg_nbits_table]
314    pxor        xmm4, xmm4                                ;A: w4[i] = 0;
315    sub         codeq, rcx                                ;Z:     code -= last_dc_val;
316    punpckldq   xmm0, xmm1                                ;A: w0 = xx 01 08 09 02 03 10 11
317    lea         t, [rsp - DCTSIZE2 * SIZEOF_WORD]         ;   use red zone for t_
318
319%endif
320
321    pshuflw     xmm0, xmm0, 11001001b                     ;A: w0 = 01 08 xx 09 02 03 10 11
322    pinsrw      xmm0, word [block + 16 * SIZEOF_WORD], 2  ;A: w0 = 01 08 16 09 02 03 10 11
323    punpckhdq   xmm3, xmm1                                ;D: w3 = 04 05 12 13 06 07 14 15
324    punpcklqdq  xmm1, xmm3                                ;B: w1 = 08 09 10 11 04 05 12 13
325    pinsrw      xmm0, word [block + 17 * SIZEOF_WORD], 7  ;A: w0 = 01 08 16 09 02 03 10 17
326                                                          ;A:      (Row 0, offset 1)
327    pcmpgtw     xmm4, xmm0                                ;A: w4[i] = (w0[i] < 0 ? -1 : 0);
328    paddw       xmm0, xmm4                                ;A: w0[i] += w4[i];
329    movaps      XMMWORD [t + 0 * SIZEOF_WORD], xmm0       ;A: t[i] = w0[i];
330
331    movq        xmm2, qword [block + 24 * SIZEOF_WORD]    ;B: w2 = 24 25 26 27 -- -- -- --
332    pshuflw     xmm2, xmm2, 11011000b                     ;B: w2 = 24 26 25 27 -- -- -- --
333    pslldq      xmm1, 1 * SIZEOF_WORD                     ;B: w1 = -- 08 09 10 11 04 05 12
334    movups      xmm5, XMMWORD [block + 48 * SIZEOF_WORD]  ;H: w5 = 48 49 50 51 52 53 54 55
335    movsd       xmm1, xmm2                                ;B: w1 = 24 26 25 27 11 04 05 12
336    punpcklqdq  xmm2, xmm5                                ;C: w2 = 24 26 25 27 48 49 50 51
337    pinsrw      xmm1, word [block + 32 * SIZEOF_WORD], 1  ;B: w1 = 24 32 25 27 11 04 05 12
338    pxor        xmm4, xmm4                                ;A: w4[i] = 0;
339    psrldq      xmm3, 2 * SIZEOF_WORD                     ;D: w3 = 12 13 06 07 14 15 -- --
340    pcmpeqw     xmm0, xmm4                                ;A: w0[i] = (w0[i] == 0 ? -1 : 0);
341    pinsrw      xmm1, word [block + 18 * SIZEOF_WORD], 3  ;B: w1 = 24 32 25 18 11 04 05 12
342                                                          ;        (Row 1, offset 1)
343    pcmpgtw     xmm4, xmm1                                ;B: w4[i] = (w1[i] < 0 ? -1 : 0);
344    paddw       xmm1, xmm4                                ;B: w1[i] += w4[i];
345    movaps      XMMWORD [t + 8 * SIZEOF_WORD], xmm1       ;B: t[i+8] = w1[i];
346    pxor        xmm4, xmm4                                ;B: w4[i] = 0;
347    pcmpeqw     xmm1, xmm4                                ;B: w1[i] = (w1[i] == 0 ? -1 : 0);
348
349    packsswb    xmm0, xmm1                                ;AB: b0[i] = w0[i], b0[i+8] = w1[i]
350                                                          ;    w/ signed saturation
351
352    pinsrw      xmm3, word [block + 20 * SIZEOF_WORD], 0  ;D: w3 = 20 13 06 07 14 15 -- --
353    pinsrw      xmm3, word [block + 21 * SIZEOF_WORD], 5  ;D: w3 = 20 13 06 07 14 21 -- --
354    pinsrw      xmm3, word [block + 28 * SIZEOF_WORD], 6  ;D: w3 = 20 13 06 07 14 21 28 --
355    pinsrw      xmm3, word [block + 35 * SIZEOF_WORD], 7  ;D: w3 = 20 13 06 07 14 21 28 35
356                                                          ;        (Row 3, offset 1)
357    pcmpgtw     xmm4, xmm3                                ;D: w4[i] = (w3[i] < 0 ? -1 : 0);
358    paddw       xmm3, xmm4                                ;D: w3[i] += w4[i];
359    movaps      XMMWORD [t + 24 * SIZEOF_WORD], xmm3      ;D: t[i+24] = w3[i];
360    pxor        xmm4, xmm4                                ;D: w4[i] = 0;
361    pcmpeqw     xmm3, xmm4                                ;D: w3[i] = (w3[i] == 0 ? -1 : 0);
362
363    pinsrw      xmm2, word [block + 19 * SIZEOF_WORD], 0  ;C: w2 = 19 26 25 27 48 49 50 51
364    cmp         code, 1 << 31                             ;Z:     Set CF if code < 0x80000000,
365                                                          ;Z:     i.e. if code is positive
366    pinsrw      xmm2, word [block + 33 * SIZEOF_WORD], 2  ;C: w2 = 19 26 33 27 48 49 50 51
367    pinsrw      xmm2, word [block + 40 * SIZEOF_WORD], 3  ;C: w2 = 19 26 33 40 48 49 50 51
368    adc         code, -1                                  ;Z:     code += -1 + (code >= 0 ? 1 : 0);
369    pinsrw      xmm2, word [block + 41 * SIZEOF_WORD], 5  ;C: w2 = 19 26 33 40 48 41 50 51
370    pinsrw      xmm2, word [block + 34 * SIZEOF_WORD], 6  ;C: w2 = 19 26 33 40 48 41 34 51
371    movsxd      codeq, code                               ;Z:     sign extend code
372    pinsrw      xmm2, word [block + 27 * SIZEOF_WORD], 7  ;C: w2 = 19 26 33 40 48 41 34 27
373                                                          ;        (Row 2, offset 1)
374    pcmpgtw     xmm4, xmm2                                ;C: w4[i] = (w2[i] < 0 ? -1 : 0);
375    paddw       xmm2, xmm4                                ;C: w2[i] += w4[i];
376    movaps      XMMWORD [t + 16 * SIZEOF_WORD], xmm2      ;C: t[i+16] = w2[i];
377    pxor        xmm4, xmm4                                ;C: w4[i] = 0;
378    pcmpeqw     xmm2, xmm4                                ;C: w2[i] = (w2[i] == 0 ? -1 : 0);
379
380    packsswb    xmm2, xmm3                                ;CD: b2[i] = w2[i], b2[i+8] = w3[i]
381                                                          ;    w/ signed saturation
382
383    movzx       nbitsq, byte [NBITS(codeq)]               ;Z:     nbits = JPEG_NBITS(code);
384    movdqa      xmm3, xmm5                                ;H: w3 = 48 49 50 51 52 53 54 55
385    pmovmskb    tempd, xmm2                               ;Z:     temp = 0;  temp |= ((b2[i] >> 7) << i);
386    pmovmskb    put_bufferd, xmm0                         ;Z:     put_buffer = 0;  put_buffer |= ((b0[i] >> 7) << i);
387    movups      xmm0, XMMWORD [block + 56 * SIZEOF_WORD]  ;H: w0 = 56 57 58 59 60 61 62 63
388    punpckhdq   xmm3, xmm0                                ;H: w3 = 52 53 60 61 54 55 62 63
389    shl         tempd, 16                                 ;Z:     temp <<= 16;
390    psrldq      xmm3, 1 * SIZEOF_WORD                     ;H: w3 = 53 60 61 54 55 62 63 --
391    pxor        xmm2, xmm2                                ;H: w2[i] = 0;
392    or          put_bufferd, tempd                        ;Z:     put_buffer |= temp;
393    pshuflw     xmm3, xmm3, 00111001b                     ;H: w3 = 60 61 54 53 55 62 63 --
394    movq        xmm1, qword [block + 44 * SIZEOF_WORD]    ;G: w1 = 44 45 46 47 -- -- -- --
395    unpcklps    xmm5, xmm0                                ;E: w5 = 48 49 56 57 50 51 58 59
396    pxor        xmm0, xmm0                                ;H: w0[i] = 0;
397    pinsrw      xmm3, word [block + 47 * SIZEOF_WORD], 3  ;H: w3 = 60 61 54 47 55 62 63 --
398                                                          ;        (Row 7, offset 1)
399    pcmpgtw     xmm2, xmm3                                ;H: w2[i] = (w3[i] < 0 ? -1 : 0);
400    paddw       xmm3, xmm2                                ;H: w3[i] += w2[i];
401    movaps      XMMWORD [t + 56 * SIZEOF_WORD], xmm3      ;H: t[i+56] = w3[i];
402    movq        xmm4, qword [block + 36 * SIZEOF_WORD]    ;G: w4 = 36 37 38 39 -- -- -- --
403    pcmpeqw     xmm3, xmm0                                ;H: w3[i] = (w3[i] == 0 ? -1 : 0);
404    punpckldq   xmm4, xmm1                                ;G: w4 = 36 37 44 45 38 39 46 47
405    mov         tempd, [dctbl + c_derived_tbl.ehufco + nbitsq * 4]
406                                                          ;Z:     temp = dctbl->ehufco[nbits];
407    movdqa      xmm1, xmm4                                ;F: w1 = 36 37 44 45 38 39 46 47
408    psrldq      xmm4, 1 * SIZEOF_WORD                     ;G: w4 = 37 44 45 38 39 46 47 --
409    shufpd      xmm1, xmm5, 10b                           ;F: w1 = 36 37 44 45 50 51 58 59
410    and         code, dword [MASK_BITS(nbitsq)]           ;Z:     code &= (1 << nbits) - 1;
411    pshufhw     xmm4, xmm4, 11010011b                     ;G: w4 = 37 44 45 38 -- 39 46 --
412    pslldq      xmm1, 1 * SIZEOF_WORD                     ;F: w1 = -- 36 37 44 45 50 51 58
413    shl         tempq, nbitsb                             ;Z:     temp <<= nbits;
414    pinsrw      xmm4, word [block + 59 * SIZEOF_WORD], 0  ;G: w4 = 59 44 45 38 -- 39 46 --
415    pshufd      xmm1, xmm1, 11011000b                     ;F: w1 = -- 36 45 50 37 44 51 58
416    pinsrw      xmm4, word [block + 52 * SIZEOF_WORD], 1  ;G: w4 = 59 52 45 38 -- 39 46 --
417    or          code, tempd                               ;Z:     code |= temp;
418    movlps      xmm1, qword [block + 20 * SIZEOF_WORD]    ;F: w1 = 20 21 22 23 37 44 51 58
419    pinsrw      xmm4, word [block + 31 * SIZEOF_WORD], 4  ;G: w4 = 59 52 45 38 31 39 46 --
420    pshuflw     xmm1, xmm1, 01110010b                     ;F: w1 = 22 20 23 21 37 44 51 58
421    pinsrw      xmm4, word [block + 53 * SIZEOF_WORD], 7  ;G: w4 = 59 52 45 38 31 39 46 53
422                                                          ;        (Row 6, offset 1)
423    pxor        xmm2, xmm2                                ;G: w2[i] = 0;
424    pcmpgtw     xmm0, xmm4                                ;G: w0[i] = (w4[i] < 0 ? -1 : 0);
425    pinsrw      xmm1, word [block + 15 * SIZEOF_WORD], 1  ;F: w1 = 22 15 23 21 37 44 51 58
426    paddw       xmm4, xmm0                                ;G: w4[i] += w0[i];
427    movaps      XMMWORD [t + 48 * SIZEOF_WORD], xmm4      ;G: t[48+i] = w4[i];
428    pinsrw      xmm1, word [block + 30 * SIZEOF_WORD], 3  ;F: w1 = 22 15 23 30 37 44 51 58
429                                                          ;        (Row 5, offset 1)
430    pcmpeqw     xmm4, xmm2                                ;G: w4[i] = (w4[i] == 0 ? -1 : 0);
431    pinsrw      xmm5, word [block + 42 * SIZEOF_WORD], 0  ;E: w5 = 42 49 56 57 50 51 58 59
432
433    packsswb    xmm4, xmm3                                ;GH: b4[i] = w4[i], b4[i+8] = w3[i]
434                                                          ;    w/ signed saturation
435
436    pxor        xmm0, xmm0                                ;F: w0[i] = 0;
437    pinsrw      xmm5, word [block + 43 * SIZEOF_WORD], 5  ;E: w5 = 42 49 56 57 50 43 58 59
438    pcmpgtw     xmm2, xmm1                                ;F: w2[i] = (w1[i] < 0 ? -1 : 0);
439    pmovmskb    tempd, xmm4                               ;Z:     temp = 0;  temp |= ((b4[i] >> 7) << i);
440    pinsrw      xmm5, word [block + 36 * SIZEOF_WORD], 6  ;E: w5 = 42 49 56 57 50 43 36 59
441    paddw       xmm1, xmm2                                ;F: w1[i] += w2[i];
442    movaps      XMMWORD [t + 40 * SIZEOF_WORD], xmm1      ;F: t[40+i] = w1[i];
443    pinsrw      xmm5, word [block + 29 * SIZEOF_WORD], 7  ;E: w5 = 42 49 56 57 50 43 36 29
444                                                          ;        (Row 4, offset 1)
445%undef block
446%define free_bitsq  rdx
447%define free_bitsd  edx
448%define free_bitsb  dl
449    pcmpeqw     xmm1, xmm0                                ;F: w1[i] = (w1[i] == 0 ? -1 : 0);
450    shl         tempq, 48                                 ;Z:     temp <<= 48;
451    pxor        xmm2, xmm2                                ;E: w2[i] = 0;
452    pcmpgtw     xmm0, xmm5                                ;E: w0[i] = (w5[i] < 0 ? -1 : 0);
453    paddw       xmm5, xmm0                                ;E: w5[i] += w0[i];
454    or          tempq, put_buffer                         ;Z:     temp |= put_buffer;
455    movaps      XMMWORD [t + 32 * SIZEOF_WORD], xmm5      ;E: t[32+i] = w5[i];
456    lea         t, [dword t - 2]                          ;Z:     t = &t[-1];
457    pcmpeqw     xmm5, xmm2                                ;E: w5[i] = (w5[i] == 0 ? -1 : 0);
458
459    packsswb    xmm5, xmm1                                ;EF: b5[i] = w5[i], b5[i+8] = w1[i]
460                                                          ;    w/ signed saturation
461
462    add         nbitsb, byte [dctbl + c_derived_tbl.ehufsi + nbitsq]
463                                                          ;Z:     nbits += dctbl->ehufsi[nbits];
464%undef dctbl
465%define code_temp  r8d
466    pmovmskb    indexd, xmm5                              ;Z:     index = 0;  index |= ((b5[i] >> 7) << i);
467    mov         free_bitsd, [state+working_state.cur.free_bits]
468                                                          ;Z:     free_bits = state->cur.free_bits;
469    pcmpeqw     xmm1, xmm1                                ;Z:     b1[i] = 0xFF;
470    shl         index, 32                                 ;Z:     index <<= 32;
471    mov         put_buffer, [state+working_state.cur.put_buffer.simd]
472                                                          ;Z:     put_buffer = state->cur.put_buffer.simd;
473    or          index, tempq                              ;Z:     index |= temp;
474    not         index                                     ;Z:     index = ~index;
475    sub         free_bitsb, nbitsb                        ;Z:     if ((free_bits -= nbits) >= 0)
476    jnl         .ENTRY_SKIP_EMIT_CODE                     ;Z:       goto .ENTRY_SKIP_EMIT_CODE;
477    align       16
478.EMIT_CODE:                                               ;Z:     .EMIT_CODE:
479    EMIT_QWORD  .BLOOP_COND                               ;Z:     insert code, flush buffer, goto .BLOOP_COND
480
481; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
482
483    align       16
484.BRLOOP:                                                  ; do {
485    lea         code_temp, [nbitsq - 16]                  ;   code_temp = nbits - 16;
486    movzx       nbits, byte [actbl + c_derived_tbl.ehufsi + 0xf0]
487                                                          ;   nbits = actbl->ehufsi[0xf0];
488    mov         code, [actbl + c_derived_tbl.ehufco + 0xf0 * 4]
489                                                          ;   code = actbl->ehufco[0xf0];
490    sub         free_bitsb, nbitsb                        ;   if ((free_bits -= nbits) <= 0)
491    jle         .EMIT_BRLOOP_CODE                         ;     goto .EMIT_BRLOOP_CODE;
492    shl         put_buffer, nbitsb                        ;   put_buffer <<= nbits;
493    mov         nbits, code_temp                          ;   nbits = code_temp;
494    or          put_buffer, codeq                         ;   put_buffer |= code;
495    cmp         nbits, 16                                 ;   if (nbits <= 16)
496    jle         .ERLOOP                                   ;     break;
497    jmp         .BRLOOP                                   ; } while (1);
498
499; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
500
501    align       16
502    times 5     nop
503.ENTRY_SKIP_EMIT_CODE:                                    ; .ENTRY_SKIP_EMIT_CODE:
504    shl         put_buffer, nbitsb                        ; put_buffer <<= nbits;
505    or          put_buffer, codeq                         ; put_buffer |= code;
506.BLOOP_COND:                                              ; .BLOOP_COND:
507    test        index, index                              ; if (index != 0)
508    jz          .ELOOP                                    ; {
509.BLOOP:                                                   ;   do {
510    xor         nbits, nbits                              ;     nbits = 0;  /* kill tzcnt input dependency */
511    tzcnt       nbitsq, index                             ;     nbits = # of trailing 0 bits in index
512    inc         nbits                                     ;     ++nbits;
513    lea         t, [t + nbitsq * 2]                       ;     t = &t[nbits];
514    shr         index, nbitsb                             ;     index >>= nbits;
515.EMIT_BRLOOP_CODE_END:                                    ; .EMIT_BRLOOP_CODE_END:
516    cmp         nbits, 16                                 ;     if (nbits > 16)
517    jg          .BRLOOP                                   ;       goto .BRLOOP;
518.ERLOOP:                                                  ; .ERLOOP:
519    movsx       codeq, word [t]                           ;     code = *t;
520    lea         tempd, [nbitsq * 2]                       ;     temp = nbits * 2;
521    movzx       nbits, byte [NBITS(codeq)]                ;     nbits = JPEG_NBITS(code);
522    lea         tempd, [nbitsq + tempq * 8]               ;     temp = temp * 8 + nbits;
523    mov         code_temp, [actbl + c_derived_tbl.ehufco + (tempq - 16) * 4]
524                                                          ;     code_temp = actbl->ehufco[temp-16];
525    shl         code_temp, nbitsb                         ;     code_temp <<= nbits;
526    and         code, dword [MASK_BITS(nbitsq)]           ;     code &= (1 << nbits) - 1;
527    add         nbitsb, [actbl + c_derived_tbl.ehufsi + (tempq - 16)]
528                                                          ;     free_bits -= actbl->ehufsi[temp-16];
529    or          code, code_temp                           ;     code |= code_temp;
530    sub         free_bitsb, nbitsb                        ;     if ((free_bits -= nbits) <= 0)
531    jle         .EMIT_CODE                                ;       goto .EMIT_CODE;
532    shl         put_buffer, nbitsb                        ;     put_buffer <<= nbits;
533    or          put_buffer, codeq                         ;     put_buffer |= code;
534    test        index, index
535    jnz         .BLOOP                                    ;   } while (index != 0);
536.ELOOP:                                                   ; }  /* index != 0 */
537    sub         td, esp                                   ; t -= (WIN64: &t_[0], UNIX: &t_[64]);
538%ifdef WIN64
539    cmp         td, (DCTSIZE2 - 2) * SIZEOF_WORD          ; if (t != 62)
540%else
541    cmp         td, -2 * SIZEOF_WORD                      ; if (t != -2)
542%endif
543    je          .EFN                                      ; {
544    movzx       nbits, byte [actbl + c_derived_tbl.ehufsi + 0]
545                                                          ;   nbits = actbl->ehufsi[0];
546    mov         code, [actbl + c_derived_tbl.ehufco + 0]  ;   code = actbl->ehufco[0];
547    sub         free_bitsb, nbitsb                        ;   if ((free_bits -= nbits) <= 0)
548    jg          .EFN_SKIP_EMIT_CODE                       ;   {
549    EMIT_QWORD  .EFN                                      ;     insert code, flush buffer
550    align       16
551.EFN_SKIP_EMIT_CODE:                                      ;   } else {
552    shl         put_buffer, nbitsb                        ;     put_buffer <<= nbits;
553    or          put_buffer, codeq                         ;     put_buffer |= code;
554.EFN:                                                     ; } }
555    mov         [state + working_state.cur.put_buffer.simd], put_buffer
556                                                          ; state->cur.put_buffer.simd = put_buffer;
557    mov         byte [state + working_state.cur.free_bits], free_bitsb
558                                                          ; state->cur.free_bits = free_bits;
559%ifdef WIN64
560    sub         rsp, -DCTSIZE2 * SIZEOF_WORD
561    pop         r12
562    pop         rdi
563    pop         rsi
564    pop         rbp
565    pop         rbx
566%else
567    pop         r12
568    pop         rbp
569    pop         rbx
570%endif
571    ret
572
573; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
574
575    align       16
576.EMIT_BRLOOP_CODE:
577    EMIT_QWORD  .EMIT_BRLOOP_CODE_END, { mov nbits, code_temp }
578                                                          ; insert code, flush buffer,
579                                                          ; nbits = code_temp, goto .EMIT_BRLOOP_CODE_END
580
581; For some reason, the OS X linker does not honor the request to align the
582; segment unless we do this.
583    align       32
584