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| author | Richard Henderson <richard.henderson@linaro.org> | 2021-06-13 16:16:25 +0000 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2021-06-29 10:04:57 -0700 |
| commit | 783d3ecdda97f0f332afa9de1cfa6fac100db31c (patch) | |
| tree | a13a76810b7362434ba030295576bd145a384f85 /tcg | |
| parent | 05dd01fa5ade816899dcf104e71ecf8a90577301 (diff) | |
| download | qemu-783d3ecdda97f0f332afa9de1cfa6fac100db31c.zip qemu-783d3ecdda97f0f332afa9de1cfa6fac100db31c.tar.gz qemu-783d3ecdda97f0f332afa9de1cfa6fac100db31c.tar.bz2 | |
tcg/ppc: Split out tcg_out_bswap16
With the use of a suitable temporary, we can use the same
algorithm when src overlaps dst. The result is the same
number of instructions either way.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'tcg')
| -rw-r--r-- | tcg/ppc/tcg-target.c.inc | 34 |
1 files changed, 19 insertions, 15 deletions
diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc index 5034718..ad46ce3 100644 --- a/tcg/ppc/tcg-target.c.inc +++ b/tcg/ppc/tcg-target.c.inc @@ -789,6 +789,24 @@ static inline void tcg_out_sari64(TCGContext *s, TCGReg dst, TCGReg src, int c) tcg_out32(s, SRADI | RA(dst) | RS(src) | SH(c & 0x1f) | ((c >> 4) & 2)); } +static void tcg_out_bswap16(TCGContext *s, TCGReg dst, TCGReg src) +{ + TCGReg tmp = dst == src ? TCG_REG_R0 : dst; + + /* + * In the following, + * dep(a, b, m) -> (a & ~m) | (b & m) + * + * Begin with: src = xxxxabcd + */ + /* tmp = rol32(src, 24) & 0x000000ff = 0000000c */ + tcg_out_rlw(s, RLWINM, tmp, src, 24, 24, 31); + /* tmp = dep(tmp, rol32(src, 8), 0x0000ff00) = 000000dc */ + tcg_out_rlw(s, RLWIMI, tmp, src, 8, 16, 23); + + tcg_out_mov(s, TCG_TYPE_REG, dst, tmp); +} + /* Emit a move into ret of arg, if it can be done in one insn. */ static bool tcg_out_movi_one(TCGContext *s, TCGReg ret, tcg_target_long arg) { @@ -2779,21 +2797,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, case INDEX_op_bswap16_i32: case INDEX_op_bswap16_i64: - a0 = args[0], a1 = args[1]; - /* a1 = abcd */ - if (a0 != a1) { - /* a0 = (a1 r<< 24) & 0xff # 000c */ - tcg_out_rlw(s, RLWINM, a0, a1, 24, 24, 31); - /* a0 = (a0 & ~0xff00) | (a1 r<< 8) & 0xff00 # 00dc */ - tcg_out_rlw(s, RLWIMI, a0, a1, 8, 16, 23); - } else { - /* r0 = (a1 r<< 8) & 0xff00 # 00d0 */ - tcg_out_rlw(s, RLWINM, TCG_REG_R0, a1, 8, 16, 23); - /* a0 = (a1 r<< 24) & 0xff # 000c */ - tcg_out_rlw(s, RLWINM, a0, a1, 24, 24, 31); - /* a0 = a0 | r0 # 00dc */ - tcg_out32(s, OR | SAB(TCG_REG_R0, a0, a0)); - } + tcg_out_bswap16(s, args[0], args[1]); break; case INDEX_op_bswap32_i32: |