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| author | Jiaxun Yang <jiaxun.yang@flygoat.com> | 2020-07-18 23:35:38 +0800 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2020-07-23 17:17:05 +0200 |
| commit | d5380f068d8c28ab3d2ffcea445a2a8072c30503 (patch) | |
| tree | e05d8fefdf94be4ca96481872b4fc9800d31938f /libavutil/mips | |
| parent | d57d6def733e6324d4ec7bcbf0ef4ef7ed5e551b (diff) | |
| download | ffmpeg-d5380f068d8c28ab3d2ffcea445a2a8072c30503.tar.gz | |
libavutils: Add parse_r helper for MIPS
That helper grab from kernel code can allow us to inline
newer instructions (not implemented by the assembler) in
a elegant manner.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Shiyou Yin <yinshiyou-hf@loongson.cn>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavutil/mips')
| -rw-r--r-- | libavutil/mips/asmdefs.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/libavutil/mips/asmdefs.h b/libavutil/mips/asmdefs.h index 748119918a..76bb2b93fa 100644 --- a/libavutil/mips/asmdefs.h +++ b/libavutil/mips/asmdefs.h @@ -55,4 +55,46 @@ # define PTR_SLL "sll " #endif +/* + * parse_r var, r - Helper assembler macro for parsing register names. + * + * This converts the register name in $n form provided in \r to the + * corresponding register number, which is assigned to the variable \var. It is + * needed to allow explicit encoding of instructions in inline assembly where + * registers are chosen by the compiler in $n form, allowing us to avoid using + * fixed register numbers. + * + * It also allows newer instructions (not implemented by the assembler) to be + * transparently implemented using assembler macros, instead of needing separate + * cases depending on toolchain support. + * + * Simple usage example: + * __asm__ __volatile__("parse_r __rt, %0\n\t" + * ".insn\n\t" + * "# di %0\n\t" + * ".word (0x41606000 | (__rt << 16))" + * : "=r" (status); + */ + +/* Match an individual register number and assign to \var */ +#define _IFC_REG(n) \ + ".ifc \\r, $" #n "\n\t" \ + "\\var = " #n "\n\t" \ + ".endif\n\t" + +__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"); + #endif /* AVCODEC_MIPS_ASMDEFS_H */ |