;

; jcsample.asm - downsampling (64-bit AVX2)

;

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

; Copyright (C) 2009, 2016, D. R. Commander.

; Copyright (C) 2015, Intel Corporation.

;

; 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        64

;

; 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);

;

; r10d = JDIMENSION image_width

; r11 = int max_v_samp_factor

; r12d = JDIMENSION v_samp_factor

; r13d = JDIMENSION width_in_blocks

; r14 = JSAMPARRAY input_data

; r15 = JSAMPARRAY output_data

    align       32

    GLOBAL_FUNCTION(jsimd_h2v1_downsample_avx2)

EXTN(jsimd_h2v1_downsample_avx2):

    push        rbp

    mov         rax, rsp

    mov         rbp, rsp

    collect_args 6

    mov         ecx, r13d

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

    jz          near .return

    mov         edx, r10d

    ; -- expand_right_edge

    push        rcx

    shl         rcx, 1                  ; output_cols * 2

    sub         rcx, rdx

    jle         short .expand_end

    mov         rax, r11

    test        rax, rax

    jle         short .expand_end

    cld

    mov         rsi, r14                ; input_data

.expandloop:

    push        rax

    push        rcx

    mov         rdi, JSAMPROW [rsi]

    add         rdi, rdx

    mov         al, JSAMPLE [rdi-1]

    rep stosb

    pop         rcx

    pop         rax

    add         rsi, byte SIZEOF_JSAMPROW

    dec         rax

    jg          short .expandloop

.expand_end:

    pop         rcx                     ; output_cols

    ; -- h2v1_downsample

    mov         eax, r12d               ; rowctr

    test        eax, eax

    jle         near .return

    mov         rdx, 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         rsi, r14                ; input_data

    mov         rdi, r15                ; output_data

.rowloop:

    push        rcx

    push        rdi

    push        rsi

    mov         rsi, JSAMPROW [rsi]     ; inptr

    mov         rdi, JSAMPROW [rdi]     ; outptr

    cmp         rcx, byte SIZEOF_YMMWORD

    jae         short .columnloop

.columnloop_r24:

    ; rcx can possibly be 8, 16, 24

    cmp         rcx, 24

    jne         .columnloop_r16

    vmovdqu     ymm0, YMMWORD [rsi+0*SIZEOF_YMMWORD]

    vmovdqu     xmm1, XMMWORD [rsi+1*SIZEOF_YMMWORD]

    mov         rcx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r16:

    cmp         rcx, 16

    jne         .columnloop_r8

    vmovdqu     ymm0, YMMWORD [rsi+0*SIZEOF_YMMWORD]

    vpxor       ymm1, ymm1, ymm1

    mov         rcx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r8:

    vmovdqu     xmm0, XMMWORD[rsi+0*SIZEOF_YMMWORD]

    vpxor       ymm1, ymm1, ymm1

    mov         rcx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop:

    vmovdqu     ymm0, YMMWORD [rsi+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [rsi+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 [rdi+0*SIZEOF_YMMWORD], ymm0

    sub         rcx, byte SIZEOF_YMMWORD    ; outcol

    add         rsi, byte 2*SIZEOF_YMMWORD  ; inptr

    add         rdi, byte 1*SIZEOF_YMMWORD  ; outptr

    cmp         rcx, byte SIZEOF_YMMWORD

    jae         short .columnloop

    test        rcx, rcx

    jnz         near .columnloop_r24

    pop         rsi

    pop         rdi

    pop         rcx

    add         rsi, byte SIZEOF_JSAMPROW  ; input_data

    add         rdi, byte SIZEOF_JSAMPROW  ; output_data

    dec         rax                        ; rowctr

    jg          near .rowloop

.return:

    vzeroupper

    uncollect_args 6

    pop         rbp

    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);

;

; r10d = JDIMENSION image_width

; r11 = int max_v_samp_factor

; r12d = JDIMENSION v_samp_factor

; r13d = JDIMENSION width_in_blocks

; r14 = JSAMPARRAY input_data

; r15 = JSAMPARRAY output_data

    align       32

    GLOBAL_FUNCTION(jsimd_h2v2_downsample_avx2)

EXTN(jsimd_h2v2_downsample_avx2):

    push        rbp

    mov         rax, rsp

    mov         rbp, rsp

    collect_args 6

    mov         ecx, r13d

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

    jz          near .return

    mov         edx, r10d

    ; -- expand_right_edge

    push        rcx

    shl         rcx, 1                  ; output_cols * 2

    sub         rcx, rdx

    jle         short .expand_end

    mov         rax, r11

    test        rax, rax

    jle         short .expand_end

    cld

    mov         rsi, r14                ; input_data

.expandloop:

    push        rax

    push        rcx

    mov         rdi, JSAMPROW [rsi]

    add         rdi, rdx

    mov         al, JSAMPLE [rdi-1]

    rep stosb

    pop         rcx

    pop         rax

    add         rsi, byte SIZEOF_JSAMPROW

    dec         rax

    jg          short .expandloop

.expand_end:

    pop         rcx                     ; output_cols

    ; -- h2v2_downsample

    mov         eax, r12d               ; rowctr

    test        rax, rax

    jle         near .return

    mov         rdx, 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         rsi, r14                ; input_data

    mov         rdi, r15                ; output_data

.rowloop:

    push        rcx

    push        rdi

    push        rsi

    mov         rdx, JSAMPROW [rsi+0*SIZEOF_JSAMPROW]  ; inptr0

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

    mov         rdi, JSAMPROW [rdi]                    ; outptr

    cmp         rcx, byte SIZEOF_YMMWORD

    jae         short .columnloop

.columnloop_r24:

    cmp         rcx, 24

    jne         .columnloop_r16

    vmovdqu     ymm0, YMMWORD [rdx+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [rsi+0*SIZEOF_YMMWORD]

    vmovdqu     xmm2, XMMWORD [rdx+1*SIZEOF_YMMWORD]

    vmovdqu     xmm3, XMMWORD [rsi+1*SIZEOF_YMMWORD]

    mov         rcx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r16:

    cmp         rcx, 16

    jne         .columnloop_r8

    vmovdqu     ymm0, YMMWORD [rdx+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [rsi+0*SIZEOF_YMMWORD]

    vpxor       ymm2, ymm2, ymm2

    vpxor       ymm3, ymm3, ymm3

    mov         rcx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop_r8:

    vmovdqu     xmm0, XMMWORD [rdx+0*SIZEOF_XMMWORD]

    vmovdqu     xmm1, XMMWORD [rsi+0*SIZEOF_XMMWORD]

    vpxor       ymm2, ymm2, ymm2

    vpxor       ymm3, ymm3, ymm3

    mov         rcx, SIZEOF_YMMWORD

    jmp         short .downsample

.columnloop:

    vmovdqu     ymm0, YMMWORD [rdx+0*SIZEOF_YMMWORD]

    vmovdqu     ymm1, YMMWORD [rsi+0*SIZEOF_YMMWORD]

    vmovdqu     ymm2, YMMWORD [rdx+1*SIZEOF_YMMWORD]

    vmovdqu     ymm3, YMMWORD [rsi+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 [rdi+0*SIZEOF_YMMWORD], ymm0

    sub         rcx, byte SIZEOF_YMMWORD    ; outcol

    add         rdx, byte 2*SIZEOF_YMMWORD  ; inptr0

    add         rsi, byte 2*SIZEOF_YMMWORD  ; inptr1

    add         rdi, byte 1*SIZEOF_YMMWORD  ; outptr

    cmp         rcx, byte SIZEOF_YMMWORD

    jae         near .columnloop

    test        rcx, rcx

    jnz         near .columnloop_r24

    pop         rsi

    pop         rdi

    pop         rcx

    add         rsi, byte 2*SIZEOF_JSAMPROW  ; input_data

    add         rdi, byte 1*SIZEOF_JSAMPROW  ; output_data

    dec         rax                          ; rowctr

    jg          near .rowloop

.return:

    vzeroupper

    uncollect_args 6

    pop         rbp

    ret

; For some reason, the OS X linker does not honor the request to align the

; segment unless we do this.

    align       32