| commit | 09aac1266e8acd02f1beb7adc91286716d7162bd | |
| author | Richard Henderson <rth@twiddle.net> | |
| Thu, 14 Jan 2010 22:59:51 +0000 (14 14:59 -0800) | ||
| committer | Aurelien Jarno <aurelien@aurel32.net> | |
| Fri, 15 Jan 2010 06:32:56 +0000 (15 07:32 +0100) | ||
| tree | a2b52e694ff69cd882913ba80cc20ee5331a4ccf | treesnapshot (tar.gz zip) |
| parent | fccd2613d6225f3cb10e861eb64fd7ce3f55eb8b | commitdiff |
tcg/x86_64: Avoid unnecessary REX.B prefixes.
The existing P_REXB internal opcode flag unconditionally emits
the REX prefix. Technically it's not needed if the register in
question is %al, %bl, %cl, %dl.
Eliding the prefix requires splitting the P_REXB flag into two,
in order to indicate whether the byte register in question is
in the REG or the R/M field. Within TCG, the byte register is
in the REG field only for stores.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
The existing P_REXB internal opcode flag unconditionally emits
the REX prefix. Technically it's not needed if the register in
question is %al, %bl, %cl, %dl.
Eliding the prefix requires splitting the P_REXB flag into two,
in order to indicate whether the byte register in question is
in the REG or the R/M field. Within TCG, the byte register is
in the REG field only for stores.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
| tcg/x86_64/tcg-target.c | diffblobblamehistory |