CoCalc -- cpu-a.S

05. Matplotlib / ffmpeg-3.0 / libx264 / common / arm / cpu-a.S
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/*****************************************************************************
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 * cpu-a.S: arm cpu detection
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 *****************************************************************************
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 * Copyright (C) 2009-2016 x264 project
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 *
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 * Authors: David Conrad <[email protected]>
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
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 *
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 * This program is also available under a commercial proprietary license.
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 * For more information, contact us at [email protected].
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 *****************************************************************************/
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#include "asm.S"
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.align 2
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// done in gas because .fpu neon overrides the refusal to assemble
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// instructions the selected -march/-mcpu doesn't support
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function x264_cpu_neon_test
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    vadd.i16    q0, q0, q0
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    bx          lr
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endfunc
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// return: 0 on success
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//         1 if counters were already enabled
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//         9 if lo-res counters were already enabled
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function x264_cpu_enable_armv7_counter, export=0
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    mrc         p15, 0, r2, c9, c12, 0      // read PMNC
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    ands        r0, r2, #1
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    andne       r0, r2, #9
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    orr         r2, r2, #1                  // enable counters
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    bic         r2, r2, #8                  // full resolution
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    mcreq       p15, 0, r2, c9, c12, 0      // write PMNC
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    mov         r2, #1 << 31                // enable cycle counter
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    mcr         p15, 0, r2, c9, c12, 1      // write CNTENS
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    bx          lr
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endfunc
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function x264_cpu_disable_armv7_counter, export=0
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    mrc         p15, 0, r0, c9, c12, 0      // read PMNC
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    bic         r0, r0, #1                  // disable counters
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    mcr         p15, 0, r0, c9, c12, 0      // write PMNC
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    bx          lr
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endfunc
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.macro READ_TIME r
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    mrc         p15, 0, \r, c9, c13, 0
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.endm
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// return: 0 if transfers neon -> arm transfers take more than 10 cycles
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//         nonzero otherwise
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function x264_cpu_fast_neon_mrc_test
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    // check for user access to performance counters
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    mrc         p15, 0, r0, c9, c14, 0
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    cmp         r0, #0
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    bxeq        lr
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    push        {r4-r6,lr}
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    bl          x264_cpu_enable_armv7_counter
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    ands        r1, r0, #8
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    mov         r3, #0
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    mov         ip, #4
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    mov         r6, #4
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    moveq       r5, #1
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    movne       r5, #64
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average_loop:
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    mov         r4, r5
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    READ_TIME   r1
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1:  subs        r4, r4, #1
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.rept 8
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    vmov.u32    lr, d0[0]
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    add         lr, lr, lr
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.endr
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    bgt         1b
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    READ_TIME   r2
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    subs        r6, r6, #1
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    sub         r2, r2, r1
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    cmpgt       r2, #30 << 3    // assume context switch if it took over 30 cycles
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    addle       r3, r3, r2
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    subsle      ip, ip, #1
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    bgt         average_loop
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    // disable counters if we enabled them
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    ands        r0, r0, #1
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    bleq        x264_cpu_disable_armv7_counter
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    lsr         r0, r3, #5
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    cmp         r0, #10
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    movgt       r0, #0
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    pop         {r4-r6,pc}
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endfunc
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