;
; jchuff-sse2-64.asm - Huffman entropy encoding (64-bit SSE2)
;
; Copyright 2009-2011, 2014-2016 D. R. Commander.
; Copyright 2015 Matthieu Darbois
;
; Based on
; 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 an SSE2 implementation for Huffman coding of one block.
; The following code is based directly on jchuff.c; see jchuff.c for more
; details.
;
; [TAB8]

%include "jsimdext.inc"

; --------------------------------------------------------------------------
        SECTION SEG_CONST

        alignz  16
        global  EXTN(jconst_huff_encode_one_block) PRIVATE

EXTN(jconst_huff_encode_one_block):

%include "jpeg_nbits_table.inc"

        alignz  16

; --------------------------------------------------------------------------
        SECTION SEG_TEXT
        BITS    64

; These macros perform the same task as the emit_bits() function in the
; original libjpeg code.  In addition to reducing overhead by explicitly
; inlining the code, additional performance is achieved by taking into
; account the size of the bit buffer and waiting until it is almost full
; before emptying it.  This mostly benefits 64-bit platforms, since 6
; bytes can be stored in a 64-bit bit buffer before it has to be emptied.

%macro EMIT_BYTE 0
        sub put_bits, 8  ; put_bits -= 8;
        mov rdx, put_buffer
        mov ecx, put_bits
        shr rdx, cl  ; c = (JOCTET)GETJOCTET(put_buffer >> put_bits);
        mov byte [buffer], dl  ; *buffer++ = c;
        add buffer, 1
        cmp dl, 0xFF  ; need to stuff a zero byte?
        jne %%.EMIT_BYTE_END
        mov byte [buffer], 0  ; *buffer++ = 0;
        add buffer, 1
%%.EMIT_BYTE_END:
%endmacro

%macro PUT_BITS 1
        add put_bits, ecx  ; put_bits += size;
        shl put_buffer, cl  ; put_buffer = (put_buffer << size);
        or  put_buffer, %1
%endmacro

%macro CHECKBUF31 0
        cmp put_bits, 32  ; if (put_bits > 31) {
        jl %%.CHECKBUF31_END
        EMIT_BYTE
        EMIT_BYTE
        EMIT_BYTE
        EMIT_BYTE
%%.CHECKBUF31_END:
%endmacro

%macro CHECKBUF47 0
        cmp put_bits, 48  ; if (put_bits > 47) {
        jl %%.CHECKBUF47_END
        EMIT_BYTE
        EMIT_BYTE
        EMIT_BYTE
        EMIT_BYTE
        EMIT_BYTE
        EMIT_BYTE
%%.CHECKBUF47_END:
%endmacro

%macro EMIT_BITS 2
        CHECKBUF47
        mov ecx, %2
        PUT_BITS %1
%endmacro

%macro kloop_prepare 37  ;(ko, jno0, ..., jno31, xmm0, xmm1, xmm2, xmm3)
    pxor xmm8, xmm8  ; __m128i neg = _mm_setzero_si128();
    pxor xmm9, xmm9  ; __m128i neg = _mm_setzero_si128();
    pxor xmm10, xmm10  ; __m128i neg = _mm_setzero_si128();
    pxor xmm11, xmm11  ; __m128i neg = _mm_setzero_si128();
    pinsrw %34, word [r12 + %2  * SIZEOF_WORD], 0  ; xmm_shadow[0] = block[jno0];
    pinsrw %35, word [r12 + %10 * SIZEOF_WORD], 0  ; xmm_shadow[8] = block[jno8];
    pinsrw %36, word [r12 + %18 * SIZEOF_WORD], 0  ; xmm_shadow[16] = block[jno16];
    pinsrw %37, word [r12 + %26 * SIZEOF_WORD], 0  ; xmm_shadow[24] = block[jno24];
    pinsrw %34, word [r12 + %3  * SIZEOF_WORD], 1  ; xmm_shadow[1] = block[jno1];
    pinsrw %35, word [r12 + %11 * SIZEOF_WORD], 1  ; xmm_shadow[9] = block[jno9];
    pinsrw %36, word [r12 + %19 * SIZEOF_WORD], 1  ; xmm_shadow[17] = block[jno17];
    pinsrw %37, word [r12 + %27 * SIZEOF_WORD], 1  ; xmm_shadow[25] = block[jno25];
    pinsrw %34, word [r12 + %4  * SIZEOF_WORD], 2  ; xmm_shadow[2] = block[jno2];
    pinsrw %35, word [r12 + %12 * SIZEOF_WORD], 2  ; xmm_shadow[10] = block[jno10];
    pinsrw %36, word [r12 + %20 * SIZEOF_WORD], 2  ; xmm_shadow[18] = block[jno18];
    pinsrw %37, word [r12 + %28 * SIZEOF_WORD], 2  ; xmm_shadow[26] = block[jno26];
    pinsrw %34, word [r12 + %5  * SIZEOF_WORD], 3  ; xmm_shadow[3] = block[jno3];
    pinsrw %35, word [r12 + %13 * SIZEOF_WORD], 3  ; xmm_shadow[11] = block[jno11];
    pinsrw %36, word [r12 + %21 * SIZEOF_WORD], 3  ; xmm_shadow[19] = block[jno19];
    pinsrw %37, word [r12 + %29 * SIZEOF_WORD], 3  ; xmm_shadow[27] = block[jno27];
    pinsrw %34, word [r12 + %6  * SIZEOF_WORD], 4  ; xmm_shadow[4] = block[jno4];
    pinsrw %35, word [r12 + %14 * SIZEOF_WORD], 4  ; xmm_shadow[12] = block[jno12];
    pinsrw %36, word [r12 + %22 * SIZEOF_WORD], 4  ; xmm_shadow[20] = block[jno20];
    pinsrw %37, word [r12 + %30 * SIZEOF_WORD], 4  ; xmm_shadow[28] = block[jno28];
    pinsrw %34, word [r12 + %7  * SIZEOF_WORD], 5  ; xmm_shadow[5] = block[jno5];
    pinsrw %35, word [r12 + %15 * SIZEOF_WORD], 5  ; xmm_shadow[13] = block[jno13];
    pinsrw %36, word [r12 + %23 * SIZEOF_WORD], 5  ; xmm_shadow[21] = block[jno21];
    pinsrw %37, word [r12 + %31 * SIZEOF_WORD], 5  ; xmm_shadow[29] = block[jno29];
    pinsrw %34, word [r12 + %8  * SIZEOF_WORD], 6  ; xmm_shadow[6] = block[jno6];
    pinsrw %35, word [r12 + %16 * SIZEOF_WORD], 6  ; xmm_shadow[14] = block[jno14];
    pinsrw %36, word [r12 + %24 * SIZEOF_WORD], 6  ; xmm_shadow[22] = block[jno22];
    pinsrw %37, word [r12 + %32 * SIZEOF_WORD], 6  ; xmm_shadow[30] = block[jno30];
    pinsrw %34, word [r12 + %9  * SIZEOF_WORD], 7  ; xmm_shadow[7] = block[jno7];
    pinsrw %35, word [r12 + %17 * SIZEOF_WORD], 7  ; xmm_shadow[15] = block[jno15];
    pinsrw %36, word [r12 + %25 * SIZEOF_WORD], 7  ; xmm_shadow[23] = block[jno23];
%if %1 != 32
    pinsrw %37, word [r12 + %33 * SIZEOF_WORD], 7  ; xmm_shadow[31] = block[jno31];
%else
    pinsrw %37, ebx, 7  ; xmm_shadow[31] = block[jno31];
%endif
    pcmpgtw xmm8, %34  ; neg = _mm_cmpgt_epi16(neg, x1);
    pcmpgtw xmm9, %35  ; neg = _mm_cmpgt_epi16(neg, x1);
    pcmpgtw xmm10, %36  ; neg = _mm_cmpgt_epi16(neg, x1);
    pcmpgtw xmm11, %37  ; neg = _mm_cmpgt_epi16(neg, x1);
    paddw %34, xmm8   ; x1 = _mm_add_epi16(x1, neg);
    paddw %35, xmm9   ; x1 = _mm_add_epi16(x1, neg);
    paddw %36, xmm10  ; x1 = _mm_add_epi16(x1, neg);
    paddw %37, xmm11  ; x1 = _mm_add_epi16(x1, neg);
    pxor %34, xmm8    ; x1 = _mm_xor_si128(x1, neg);
    pxor %35, xmm9    ; x1 = _mm_xor_si128(x1, neg);
    pxor %36, xmm10   ; x1 = _mm_xor_si128(x1, neg);
    pxor %37, xmm11   ; x1 = _mm_xor_si128(x1, neg);
    pxor xmm8, %34    ; neg = _mm_xor_si128(neg, x1);
    pxor xmm9, %35    ; neg = _mm_xor_si128(neg, x1);
    pxor xmm10, %36   ; neg = _mm_xor_si128(neg, x1);
    pxor xmm11, %37   ; neg = _mm_xor_si128(neg, x1);
    movdqa XMMWORD [t1 + %1 * SIZEOF_WORD], %34  ; _mm_storeu_si128((__m128i *)(t1 + ko), x1);
    movdqa XMMWORD [t1 + (%1 + 8) * SIZEOF_WORD], %35  ; _mm_storeu_si128((__m128i *)(t1 + ko + 8), x1);
    movdqa XMMWORD [t1 + (%1 + 16) * SIZEOF_WORD], %36  ; _mm_storeu_si128((__m128i *)(t1 + ko + 16), x1);
    movdqa XMMWORD [t1 + (%1 + 24) * SIZEOF_WORD], %37  ; _mm_storeu_si128((__m128i *)(t1 + ko + 24), x1);
    movdqa XMMWORD [t2 + %1 * SIZEOF_WORD], xmm8  ; _mm_storeu_si128((__m128i *)(t2 + ko), neg);
    movdqa XMMWORD [t2 + (%1 + 8) * SIZEOF_WORD], xmm9  ; _mm_storeu_si128((__m128i *)(t2 + ko + 8), neg);
    movdqa XMMWORD [t2 + (%1 + 16) * SIZEOF_WORD], xmm10  ; _mm_storeu_si128((__m128i *)(t2 + ko + 16), neg);
    movdqa XMMWORD [t2 + (%1 + 24) * SIZEOF_WORD], xmm11  ; _mm_storeu_si128((__m128i *)(t2 + ko + 24), neg);
%endmacro

;
; Encode a single block's worth of coefficients.
;
; GLOBAL(JOCTET*)
; jsimd_huff_encode_one_block_sse2 (working_state *state, JOCTET *buffer,
;                                   JCOEFPTR block, int last_dc_val,
;                                   c_derived_tbl *dctbl, c_derived_tbl *actbl)
;

; r10 = working_state *state
; r11 = JOCTET *buffer
; r12 = JCOEFPTR block
; r13 = int last_dc_val
; r14 = c_derived_tbl *dctbl
; r15 = c_derived_tbl *actbl

%define t1              rbp-(DCTSIZE2*SIZEOF_WORD)
%define t2              t1-(DCTSIZE2*SIZEOF_WORD)
%define put_buffer      r8
%define put_bits        r9d
%define buffer          rax

        align   16
        global  EXTN(jsimd_huff_encode_one_block_sse2) PRIVATE

EXTN(jsimd_huff_encode_one_block_sse2):
        push    rbp
        mov     rax,rsp                         ; rax = original rbp
        sub     rsp, byte 4
        and     rsp, byte (-SIZEOF_XMMWORD)     ; align to 128 bits
        mov     [rsp],rax
        mov     rbp,rsp                         ; rbp = aligned rbp
        lea     rsp, [t2]
        collect_args
%ifdef WIN64
        movaps  XMMWORD [rsp-1*SIZEOF_XMMWORD], xmm8
        movaps  XMMWORD [rsp-2*SIZEOF_XMMWORD], xmm9
        movaps  XMMWORD [rsp-3*SIZEOF_XMMWORD], xmm10
        movaps  XMMWORD [rsp-4*SIZEOF_XMMWORD], xmm11
        sub     rsp, 4*SIZEOF_XMMWORD
%endif
        push rbx

        mov buffer, r11  ; r11 is now sratch

        mov put_buffer, MMWORD [r10+16]  ; put_buffer = state->cur.put_buffer;
        mov put_bits,    DWORD [r10+24]  ; put_bits = state->cur.put_bits;
        push r10  ; r10 is now scratch

        ; Encode the DC coefficient difference per section F.1.2.1
        movsx edi, word [r12]  ; temp = temp2 = block[0] - last_dc_val;
        sub   edi, r13d  ; r13 is not used anymore
        mov   ebx, edi

        ; This is a well-known technique for obtaining the absolute value
        ; without a branch.  It is derived from an assembly language technique
        ; presented in "How to Optimize for the Pentium Processors",
        ; Copyright (c) 1996, 1997 by Agner Fog.
        mov esi, edi
        sar esi, 31   ; temp3 = temp >> (CHAR_BIT * sizeof(int) - 1);
        xor edi, esi  ; temp ^= temp3;
        sub edi, esi  ; temp -= temp3;

        ; For a negative input, want temp2 = bitwise complement of abs(input)
        ; This code assumes we are on a two's complement machine
        add ebx, esi  ; temp2 += temp3;

        ; Find the number of bits needed for the magnitude of the coefficient
        lea   r11, [rel jpeg_nbits_table]
        movzx rdi, byte [r11 + rdi]  ; nbits = JPEG_NBITS(temp);
        ; Emit the Huffman-coded symbol for the number of bits
        mov   r11d,  INT [r14 + rdi * 4]  ; code = dctbl->ehufco[nbits];
        movzx  esi, byte [r14 + rdi + 1024]  ; size = dctbl->ehufsi[nbits];
        EMIT_BITS r11, esi  ; EMIT_BITS(code, size)

        ; Mask off any extra bits in code
        mov esi, 1
        mov ecx, edi
        shl esi, cl
        dec esi
        and ebx, esi  ; temp2 &= (((JLONG) 1)<<nbits) - 1;

        ; Emit that number of bits of the value, if positive,
        ; or the complement of its magnitude, if negative.
        EMIT_BITS rbx, edi  ; EMIT_BITS(temp2, nbits)

        ; Prepare data
        xor ebx, ebx
        kloop_prepare  0,  1,  8,  16, 9,  2,  3,  10, 17, 24, 32, 25, \
                       18, 11, 4,  5,  12, 19, 26, 33, 40, 48, 41, 34, \
                       27, 20, 13, 6,  7,  14, 21, 28, 35, \
                       xmm0, xmm1, xmm2, xmm3
        kloop_prepare  32, 42, 49, 56, 57, 50, 43, 36, 29, 22, 15, 23, \
                       30, 37, 44, 51, 58, 59, 52, 45, 38, 31, 39, 46, \
                       53, 60, 61, 54, 47, 55, 62, 63, 63, \
                       xmm4, xmm5, xmm6, xmm7

        pxor xmm8, xmm8
        pcmpeqw xmm0, xmm8  ; tmp0 = _mm_cmpeq_epi16(tmp0, zero);
        pcmpeqw xmm1, xmm8  ; tmp1 = _mm_cmpeq_epi16(tmp1, zero);
        pcmpeqw xmm2, xmm8  ; tmp2 = _mm_cmpeq_epi16(tmp2, zero);
        pcmpeqw xmm3, xmm8  ; tmp3 = _mm_cmpeq_epi16(tmp3, zero);
        pcmpeqw xmm4, xmm8  ; tmp4 = _mm_cmpeq_epi16(tmp4, zero);
        pcmpeqw xmm5, xmm8  ; tmp5 = _mm_cmpeq_epi16(tmp5, zero);
        pcmpeqw xmm6, xmm8  ; tmp6 = _mm_cmpeq_epi16(tmp6, zero);
        pcmpeqw xmm7, xmm8  ; tmp7 = _mm_cmpeq_epi16(tmp7, zero);
        packsswb xmm0, xmm1  ; tmp0 = _mm_packs_epi16(tmp0, tmp1);
        packsswb xmm2, xmm3  ; tmp2 = _mm_packs_epi16(tmp2, tmp3);
        packsswb xmm4, xmm5  ; tmp4 = _mm_packs_epi16(tmp4, tmp5);
        packsswb xmm6, xmm7  ; tmp6 = _mm_packs_epi16(tmp6, tmp7);
        pmovmskb r11d, xmm0  ; index  = ((uint64_t)_mm_movemask_epi8(tmp0)) << 0;
        pmovmskb r12d, xmm2  ; index  = ((uint64_t)_mm_movemask_epi8(tmp2)) << 16;
        pmovmskb r13d, xmm4  ; index  = ((uint64_t)_mm_movemask_epi8(tmp4)) << 32;
        pmovmskb r14d, xmm6  ; index  = ((uint64_t)_mm_movemask_epi8(tmp6)) << 48;
        shl r12, 16
        shl r14, 16
        or  r11, r12
        or  r13, r14
        shl r13, 32
        or  r11, r13
        not r11  ; index = ~index;

        ;mov MMWORD [ t1 + DCTSIZE2 * SIZEOF_WORD ], r11
        ;jmp .EFN

        mov   r13d,  INT [r15 + 240 * 4]  ; code_0xf0 = actbl->ehufco[0xf0];
        movzx r14d, byte [r15 + 1024 + 240]  ; size_0xf0 = actbl->ehufsi[0xf0];
        lea rsi, [t1]
.BLOOP:
        bsf r12, r11  ; r = __builtin_ctzl(index);
        jz .ELOOP
        mov rcx, r12
        lea rsi, [rsi+r12*2]  ; k += r;
        shr r11, cl  ; index >>= r;
        movzx rdi, word [rsi]  ; temp = t1[k];
        lea   rbx, [rel jpeg_nbits_table]
        movzx rdi, byte [rbx + rdi]  ; nbits = JPEG_NBITS(temp);
.BRLOOP:
        cmp r12, 16  ; while (r > 15) {
        jl .ERLOOP
        EMIT_BITS r13, r14d  ; EMIT_BITS(code_0xf0, size_0xf0)
        sub r12, 16  ; r -= 16;
        jmp .BRLOOP
.ERLOOP:
        ; Emit Huffman symbol for run length / number of bits
        CHECKBUF31  ; uses rcx, rdx

        shl r12, 4  ; temp3 = (r << 4) + nbits;
        add r12, rdi
        mov   ebx,  INT [r15 + r12 * 4]  ; code = actbl->ehufco[temp3];
        movzx ecx, byte [r15 + r12 + 1024]  ; size = actbl->ehufsi[temp3];
        PUT_BITS rbx

        ;EMIT_CODE(code, size)

        movsx ebx, word [rsi-DCTSIZE2*2]  ; temp2 = t2[k];
        ; Mask off any extra bits in code
        mov rcx, rdi
        mov rdx, 1
        shl rdx, cl
        dec rdx
        and rbx, rdx  ; temp2 &= (((JLONG) 1)<<nbits) - 1;
        PUT_BITS rbx  ; PUT_BITS(temp2, nbits)

        shr r11, 1  ; index >>= 1;
        add rsi, 2  ; ++k;
        jmp .BLOOP
.ELOOP:
        ; If the last coef(s) were zero, emit an end-of-block code
        lea rdi, [t1 + (DCTSIZE2-1) * 2]  ; r = DCTSIZE2-1-k;
        cmp rdi, rsi  ; if (r > 0) {
        je .EFN
        mov   ebx,  INT [r15]  ; code = actbl->ehufco[0];
        movzx r12d, byte [r15 + 1024]  ; size = actbl->ehufsi[0];
        EMIT_BITS rbx, r12d
.EFN:
        pop r10
        ; Save put_buffer & put_bits
        mov MMWORD [r10+16], put_buffer  ; state->cur.put_buffer = put_buffer;
        mov DWORD  [r10+24], put_bits  ; state->cur.put_bits = put_bits;

        pop rbx
%ifdef WIN64
        movaps  xmm11, XMMWORD [rsp+0*SIZEOF_XMMWORD]
        movaps  xmm10, XMMWORD [rsp+1*SIZEOF_XMMWORD]
        movaps  xmm9, XMMWORD [rsp+2*SIZEOF_XMMWORD]
        movaps  xmm8, XMMWORD [rsp+3*SIZEOF_XMMWORD]
        add     rsp, 4*SIZEOF_XMMWORD
%endif
        uncollect_args
        mov     rsp,rbp         ; rsp <- aligned rbp
        pop     rsp             ; rsp <- original rbp
        pop     rbp
        ret

; For some reason, the OS X linker does not honor the request to align the
; segment unless we do this.
        align   16
