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| author | Richard Henderson <rth@twiddle.net> | 2015-08-05 11:04:11 -0700 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2015-08-18 09:11:12 -0700 |
| commit | 112e4518f0d38fc3c52e55c7d7e77b66a295ec2b (patch) | |
| tree | fc55cbf2eebfa7d52d0702222ee0cbac570f3af1 /target-alpha | |
| parent | 5f2a80adc6fd2b2e4e0579a6613a9913e3cc9a05 (diff) | |
| download | qemu-112e4518f0d38fc3c52e55c7d7e77b66a295ec2b.tar.gz qemu-112e4518f0d38fc3c52e55c7d7e77b66a295ec2b.tar.bz2 qemu-112e4518f0d38fc3c52e55c7d7e77b66a295ec2b.zip | |
target-alpha: Special case cmpbge with zero
Knowing the comparator is zero leads to a simpler operation.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'target-alpha')
| -rw-r--r-- | target-alpha/helper.h | 1 | ||||
| -rw-r--r-- | target-alpha/int_helper.c | 14 | ||||
| -rw-r--r-- | target-alpha/translate.c | 7 |
3 files changed, 21 insertions, 1 deletions
diff --git a/target-alpha/helper.h b/target-alpha/helper.h index d221f0d7d6..83cbe2abda 100644 --- a/target-alpha/helper.h +++ b/target-alpha/helper.h @@ -10,6 +10,7 @@ DEF_HELPER_FLAGS_1(cttz, TCG_CALL_NO_RWG_SE, i64, i64) DEF_HELPER_FLAGS_2(zap, TCG_CALL_NO_RWG_SE, i64, i64, i64) DEF_HELPER_FLAGS_2(zapnot, TCG_CALL_NO_RWG_SE, i64, i64, i64) +DEF_HELPER_FLAGS_1(cmpbe0, TCG_CALL_NO_RWG_SE, i64, i64) DEF_HELPER_FLAGS_2(cmpbge, TCG_CALL_NO_RWG_SE, i64, i64, i64) DEF_HELPER_FLAGS_2(minub8, TCG_CALL_NO_RWG_SE, i64, i64, i64) diff --git a/target-alpha/int_helper.c b/target-alpha/int_helper.c index 4a6e95512b..d7f4774127 100644 --- a/target-alpha/int_helper.c +++ b/target-alpha/int_helper.c @@ -58,6 +58,20 @@ uint64_t helper_zap(uint64_t val, uint64_t mask) return helper_zapnot(val, ~mask); } +uint64_t helper_cmpbe0(uint64_t a) +{ + uint64_t m = 0x7f7f7f7f7f7f7f7fULL; + uint64_t c = ~(((a & m) + m) | a | m); + /* a.......b.......c.......d.......e.......f.......g.......h....... */ + c |= c << 7; + /* ab......bc......cd......de......ef......fg......gh......h....... */ + c |= c << 14; + /* abcd....bcde....cdef....defg....efgh....fgh.....gh......h....... */ + c |= c << 28; + /* abcdefghbcdefgh.cdefgh..defgh...efgh....fgh.....gh......h....... */ + return c >> 56; +} + uint64_t helper_cmpbge(uint64_t a, uint64_t b) { uint64_t mask = 0x00ff00ff00ff00ffULL; diff --git a/target-alpha/translate.c b/target-alpha/translate.c index 81d4ff827c..b766ae3daa 100644 --- a/target-alpha/translate.c +++ b/target-alpha/translate.c @@ -1507,7 +1507,12 @@ static ExitStatus translate_one(DisasContext *ctx, uint32_t insn) break; case 0x0F: /* CMPBGE */ - gen_helper_cmpbge(vc, va, vb); + if (ra == 31) { + /* Special case 0 >= X as X == 0. */ + gen_helper_cmpbe0(vc, vb); + } else { + gen_helper_cmpbge(vc, va, vb); + } break; case 0x12: /* S8ADDL */ |