FFmpeg
cpu.h
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1 /*
2  * Copyright © 2022 Rémi Denis-Courmont.
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVUTIL_RISCV_CPU_H
22 #define AVUTIL_RISCV_CPU_H
23 
24 #include "config.h"
25 #include <stdbool.h>
26 #include <stddef.h>
27 #include "libavutil/cpu.h"
28 
29 #if HAVE_RVV
30 /**
31  * Returns the vector size in bytes (always a power of two and at least 4).
32  * This is undefined behaviour if vectors are not implemented.
33  */
34 static inline size_t ff_get_rv_vlenb(void)
35 {
36  size_t vlenb;
37 
38  __asm__ (
39  ".option push\n"
40  ".option arch, +v\n"
41  " csrr %0, vlenb\n"
42  ".option pop\n" : "=r" (vlenb));
43  return vlenb;
44 }
45 #endif
46 
47 /**
48  * Checks that the vector bit-size is at least the given value.
49  * This is potentially undefined behaviour if vectors are not implemented.
50  */
51 static inline bool ff_rv_vlen_least(unsigned int bits)
52 {
53 #ifdef __riscv_v_min_vlen
54  if (bits <= __riscv_min_vlen)
55  return true;
56 #else
57  /*
58  * Vector lengths smaller than 128 bits are only possible in embedded cases
59  * and cannot be run-time detected, so we can assume 128 bits at least.
60  */
61  if (bits <= 128)
62  return true;
63 #endif
64  return bits <= (8 * ff_get_rv_vlenb());
65 }
66 #endif
ff_rv_vlen_least
static bool ff_rv_vlen_least(unsigned int bits)
Checks that the vector bit-size is at least the given value.
Definition: cpu.h:51
bits
uint8_t bits
Definition: vp3data.h:128
cpu.h
__asm__
__asm__(".macro parse_r var r\n\t" "\\var = -1\n\t" _IFC_REG(0) _IFC_REG(1) _IFC_REG(2) _IFC_REG(3) _IFC_REG(4) _IFC_REG(5) _IFC_REG(6) _IFC_REG(7) _IFC_REG(8) _IFC_REG(9) _IFC_REG(10) _IFC_REG(11) _IFC_REG(12) _IFC_REG(13) _IFC_REG(14) _IFC_REG(15) _IFC_REG(16) _IFC_REG(17) _IFC_REG(18) _IFC_REG(19) _IFC_REG(20) _IFC_REG(21) _IFC_REG(22) _IFC_REG(23) _IFC_REG(24) _IFC_REG(25) _IFC_REG(26) _IFC_REG(27) _IFC_REG(28) _IFC_REG(29) _IFC_REG(30) _IFC_REG(31) ".iflt \\var\n\t" ".error \"Unable to parse register name \\r\"\n\t" ".endif\n\t" ".endm")