;

; jcsample.asm - downsampling (AVX2)

;

; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB</ossman@cendio.se>

; Copyright (C) 2015, Intel Corporation.

; 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

%include "jsimdext.inc"

; --------------------------------------------------------------------------

    SECTION     SEG_TEXT

    BITS        32

;

; Downsample pixel values of a single component.

; This version handles the common case of 2:1 horizontal and 1:1 vertical,

; without smoothing.

;

; GLOBAL(void)

; jsimd_h2v1_downsample_avx2(JDIMENSION image_width, int max_v_samp_factor,

;                            JDIMENSION v_samp_factor,

;                            JDIMENSION width_in_blocks, JSAMPARRAY input_data,

;                            JSAMPARRAY output_data);

;

%define img_width(b)    (b) + 8         ; JDIMENSION image_width

%define max_v_samp(b)   (b) + 12        ; int max_v_samp_factor

%define v_samp(b)       (b) + 16        ; JDIMENSION v_samp_factor

%define width_blks(b)   (b) + 20        ; JDIMENSION width_in_blocks

%define input_data(b)   (b) + 24        ; JSAMPARRAY input_data

%define output_data(b)  (b) + 28        ; JSAMPARRAY output_data

    align       32

    GLOBAL_FUNCTION(jsimd_h2v1_downsample_avx2)

EXTN(jsimd_h2v1_downsample_avx2):

    push        ebp

    mov         ebp, esp

;   push        ebx                     ; unused

;   push        ecx                     ; need not be preserved

;   push        edx                     ; need not be preserved

    push        esi

    push        edi

    mov         ecx, JDIMENSION [width_blks(ebp)]

    shl         ecx, 3                  ; imul ecx,DCTSIZE (ecx = output_cols)

    jz          near .return

    mov         edx, JDIMENSION [img_width(ebp)]

    ; -- expand_right_edge

    push        ecx

    shl         ecx, 1                  ; output_cols * 2

    sub         ecx, edx

    jle         short .expand_end

    mov         eax, INT [max_v_samp(ebp)]

    test        eax, eax

    jle         short .expand_end

    cld

    mov         esi, JSAMPARRAY [input_data(ebp)]  ; input_data

    alignx      16, 7

.expandloop:

    push        eax

    push        ecx

    mov         edi, JSAMPROW [esi]

    add         edi, edx

    mov         al, JSAMPLE [edi-1]

    rep stosb

    pop         ecx

    pop         eax

    add         esi, byte SIZEOF_JSAMPROW

    dec         eax

    jg          short .expandloop

.expand_end:

    pop         ecx                     ; output_cols

    ; -- h2v1_downsample

    mov         eax, JDIMENSION [v_samp(ebp)]  ; rowctr

    test        eax, eax

    jle         near .return

    mov         edx, 0x00010000         ; bias pattern

    vmovd       xmm7, edx

    vpshufd     xmm7, xmm7, 0x00        ; xmm7={0, 1, 0, 1, 0, 1, 0, 1}

    vperm2i128  ymm7, ymm7, ymm7, 0     ; ymm7={xmm7, xmm7}

    vpcmpeqw    ymm6, ymm6, ymm6

    vpsrlw      ymm6, ymm6, BYTE_BIT    ; ymm6={0xFF 0x00 0xFF 0x00 ..}

    mov         esi, JSAMPARRAY [input_data(ebp)]   ; input_data

    mov         edi, JSAMPARRAY [output_data(ebp)]  ; output_data

    alignx      16, 7

.rowloop:

    push        ecx

    push        edi

    push        esi

    mov         esi, JSAMPROW [esi]     ; inptr

    mov         edi, JSAMPROW [edi]     ; outptr

    cmp         ecx, byte SIZEOF_YMMWORD

    jae         short .columnloop

    alignx      16, 7

.columnloop_r24:

    ; ecx can possibly be 8, 16, 24

    cmp         ecx, 24

    jne         .columnloop_r16

    vmovdqu     ymm0, YMMWORD [esi+0*SIZEOF_YMMWORD]

    vmovdqu     xmm1, XMMWORD [esi+1*SIZEOF_YMMWORD]

    mov         ecx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r16:

    cmp         ecx, 16

    jne         .columnloop_r8

    vmovdqu     ymm0, YMMWORD [esi+0*SIZEOF_YMMWORD]

    vpxor       ymm1, ymm1, ymm1

    mov         ecx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r8:

    vmovdqu     xmm0, XMMWORD[esi+0*SIZEOF_YMMWORD]

    vpxor       ymm1, ymm1, ymm1

    mov         ecx, SIZEOF_YMMWORD

    jmp         short .downsample

    alignx      16, 7

.columnloop:

    vmovdqu     ymm0, YMMWORD [esi+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [esi+1*SIZEOF_YMMWORD]

.downsample:

    vpsrlw      ymm2, ymm0, BYTE_BIT

    vpand       ymm0, ymm0, ymm6

    vpsrlw      ymm3, ymm1, BYTE_BIT

    vpand       ymm1, ymm1, ymm6

    vpaddw      ymm0, ymm0, ymm2

    vpaddw      ymm1, ymm1, ymm3

    vpaddw      ymm0, ymm0, ymm7

    vpaddw      ymm1, ymm1, ymm7

    vpsrlw      ymm0, ymm0, 1

    vpsrlw      ymm1, ymm1, 1

    vpackuswb   ymm0, ymm0, ymm1

    vpermq      ymm0, ymm0, 0xd8

    vmovdqu     YMMWORD [edi+0*SIZEOF_YMMWORD], ymm0

    sub         ecx, byte SIZEOF_YMMWORD    ; outcol

    add         esi, byte 2*SIZEOF_YMMWORD  ; inptr

    add         edi, byte 1*SIZEOF_YMMWORD  ; outptr

    cmp         ecx, byte SIZEOF_YMMWORD

    jae         short .columnloop

    test        ecx, ecx

    jnz         near .columnloop_r24

    pop         esi

    pop         edi

    pop         ecx

    add         esi, byte SIZEOF_JSAMPROW  ; input_data

    add         edi, byte SIZEOF_JSAMPROW  ; output_data

    dec         eax                        ; rowctr

    jg          near .rowloop

.return:

    vzeroupper

    pop         edi

    pop         esi

;   pop         edx                     ; need not be preserved

;   pop         ecx                     ; need not be preserved

;   pop         ebx                     ; unused

    pop         ebp

    ret

; --------------------------------------------------------------------------

;

; Downsample pixel values of a single component.

; This version handles the standard case of 2:1 horizontal and 2:1 vertical,

; without smoothing.

;

; GLOBAL(void)

; jsimd_h2v2_downsample_avx2(JDIMENSION image_width, int max_v_samp_factor,

;                            JDIMENSION v_samp_factor,

;                            JDIMENSION width_in_blocks, JSAMPARRAY input_data,

;                            JSAMPARRAY output_data);

;

%define img_width(b)    (b) + 8         ; JDIMENSION image_width

%define max_v_samp(b)   (b) + 12        ; int max_v_samp_factor

%define v_samp(b)       (b) + 16        ; JDIMENSION v_samp_factor

%define width_blks(b)   (b) + 20        ; JDIMENSION width_in_blocks

%define input_data(b)   (b) + 24        ; JSAMPARRAY input_data

%define output_data(b)  (b) + 28        ; JSAMPARRAY output_data

    align       32

    GLOBAL_FUNCTION(jsimd_h2v2_downsample_avx2)

EXTN(jsimd_h2v2_downsample_avx2):

    push        ebp

    mov         ebp, esp

;   push        ebx                     ; unused

;   push        ecx                     ; need not be preserved

;   push        edx                     ; need not be preserved

    push        esi

    push        edi

    mov         ecx, JDIMENSION [width_blks(ebp)]

    shl         ecx, 3                  ; imul ecx,DCTSIZE (ecx = output_cols)

    jz          near .return

    mov         edx, JDIMENSION [img_width(ebp)]

    ; -- expand_right_edge

    push        ecx

    shl         ecx, 1                  ; output_cols * 2

    sub         ecx, edx

    jle         short .expand_end

    mov         eax, INT [max_v_samp(ebp)]

    test        eax, eax

    jle         short .expand_end

    cld

    mov         esi, JSAMPARRAY [input_data(ebp)]  ; input_data

    alignx      16, 7

.expandloop:

    push        eax

    push        ecx

    mov         edi, JSAMPROW [esi]

    add         edi, edx

    mov         al, JSAMPLE [edi-1]

    rep stosb

    pop         ecx

    pop         eax

    add         esi, byte SIZEOF_JSAMPROW

    dec         eax

    jg          short .expandloop

.expand_end:

    pop         ecx                     ; output_cols

    ; -- h2v2_downsample

    mov         eax, JDIMENSION [v_samp(ebp)]  ; rowctr

    test        eax, eax

    jle         near .return

    mov         edx, 0x00020001         ; bias pattern

    vmovd       xmm7, edx

    vpcmpeqw    ymm6, ymm6, ymm6

    vpshufd     xmm7, xmm7, 0x00        ; ymm7={1, 2, 1, 2, 1, 2, 1, 2}

    vperm2i128  ymm7, ymm7, ymm7, 0

    vpsrlw      ymm6, ymm6, BYTE_BIT    ; ymm6={0xFF 0x00 0xFF 0x00 ..}

    mov         esi, JSAMPARRAY [input_data(ebp)]   ; input_data

    mov         edi, JSAMPARRAY [output_data(ebp)]  ; output_data

    alignx      16, 7

.rowloop:

    push        ecx

    push        edi

    push        esi

    mov         edx, JSAMPROW [esi+0*SIZEOF_JSAMPROW]  ; inptr0

    mov         esi, JSAMPROW [esi+1*SIZEOF_JSAMPROW]  ; inptr1

    mov         edi, JSAMPROW [edi]                    ; outptr

    cmp         ecx, byte SIZEOF_YMMWORD

    jae         short .columnloop

    alignx      16, 7

.columnloop_r24:

    cmp         ecx, 24

    jne         .columnloop_r16

    vmovdqu     ymm0, YMMWORD [edx+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [esi+0*SIZEOF_YMMWORD]

    vmovdqu     xmm2, XMMWORD [edx+1*SIZEOF_YMMWORD]

    vmovdqu     xmm3, XMMWORD [esi+1*SIZEOF_YMMWORD]

    mov         ecx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r16:

    cmp         ecx, 16

    jne         .columnloop_r8

    vmovdqu     ymm0, YMMWORD [edx+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [esi+0*SIZEOF_YMMWORD]

    vpxor       ymm2, ymm2, ymm2

    vpxor       ymm3, ymm3, ymm3

    mov         ecx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r8:

    vmovdqu     xmm0, XMMWORD [edx+0*SIZEOF_XMMWORD]

    vmovdqu     xmm1, XMMWORD [esi+0*SIZEOF_XMMWORD]

    vpxor       ymm2, ymm2, ymm2

    vpxor       ymm3, ymm3, ymm3

    mov         ecx, SIZEOF_YMMWORD

    jmp         short .downsample

    alignx      16, 7

.columnloop:

    vmovdqu     ymm0, YMMWORD [edx+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [esi+0*SIZEOF_YMMWORD]

    vmovdqu     ymm2, YMMWORD [edx+1*SIZEOF_YMMWORD]

    vmovdqu     ymm3, YMMWORD [esi+1*SIZEOF_YMMWORD]

.downsample:

    vpand       ymm4, ymm0, ymm6

    vpsrlw      ymm0, ymm0, BYTE_BIT

    vpand       ymm5, ymm1, ymm6

    vpsrlw      ymm1, ymm1, BYTE_BIT

    vpaddw      ymm0, ymm0, ymm4

    vpaddw      ymm1, ymm1, ymm5

    vpand       ymm4, ymm2, ymm6

    vpsrlw      ymm2, ymm2, BYTE_BIT

    vpand       ymm5, ymm3, ymm6

    vpsrlw      ymm3, ymm3, BYTE_BIT

    vpaddw      ymm2, ymm2, ymm4

    vpaddw      ymm3, ymm3, ymm5

    vpaddw      ymm0, ymm0, ymm1

    vpaddw      ymm2, ymm2, ymm3

    vpaddw      ymm0, ymm0, ymm7

    vpaddw      ymm2, ymm2, ymm7

    vpsrlw      ymm0, ymm0, 2

    vpsrlw      ymm2, ymm2, 2

    vpackuswb   ymm0, ymm0, ymm2

    vpermq      ymm0, ymm0, 0xd8

    vmovdqu     YMMWORD [edi+0*SIZEOF_YMMWORD], ymm0

    sub         ecx, byte SIZEOF_YMMWORD    ; outcol

    add         edx, byte 2*SIZEOF_YMMWORD  ; inptr0

    add         esi, byte 2*SIZEOF_YMMWORD  ; inptr1

    add         edi, byte 1*SIZEOF_YMMWORD  ; outptr

    cmp         ecx, byte SIZEOF_YMMWORD

    jae         near .columnloop

    test        ecx, ecx

    jnz         near .columnloop_r24

    pop         esi

    pop         edi

    pop         ecx

    add         esi, byte 2*SIZEOF_JSAMPROW  ; input_data

    add         edi, byte 1*SIZEOF_JSAMPROW  ; output_data

    dec         eax                          ; rowctr

    jg          near .rowloop

.return:

    vzeroupper

    pop         edi

    pop         esi

;   pop         edx                     ; need not be preserved

;   pop         ecx                     ; need not be preserved

;   pop         ebx                     ; unused

    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