diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2020-12-14 16:13:55 -0600 |
|---|---|---|
| committer | Cornelia Huck <cohuck@redhat.com> | 2020-12-21 18:11:33 +0100 |
| commit | a2db06da7dff662159c809059cda5e2aa302ec86 (patch) | |
| tree | ca594af1e916b3496fb5f8c276fae0e2687c5c4e /target/s390x/internal.h | |
| parent | 3bcc3fa79902d72ab6385bb135e4c3e34931a697 (diff) | |
target/s390x: Improve cc computation for SUBTRACT LOGICAL
The resulting cc is only dependent on the result and the carry-out.
Carry-out and borrow-out are inverses, so are trivially converted.
With tcg ops, it is easier to compute borrow-out than carry-out, so
save result and borrow-out rather than the inputs.
Borrow-out for 64-bit inputs is had via tcg_gen_sub2_i64 directly
into cc_src. Borrow-out for 32-bit inputs is had via extraction
from a normal 64-bit sub (with zero-extended inputs).
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201214221356.68039-4-richard.henderson@linaro.org>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'target/s390x/internal.h')
| -rw-r--r-- | target/s390x/internal.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/target/s390x/internal.h b/target/s390x/internal.h index f5f3ae063e..4077047494 100644 --- a/target/s390x/internal.h +++ b/target/s390x/internal.h @@ -161,6 +161,7 @@ enum cc_op { CC_OP_NZ, /* env->cc_dst != 0 */ CC_OP_ADDU, /* dst != 0, src = carry out (0,1) */ + CC_OP_SUBU, /* dst != 0, src = borrow out (0,-1) */ CC_OP_LTGT_32, /* signed less/greater than (32bit) */ CC_OP_LTGT_64, /* signed less/greater than (64bit) */ @@ -171,7 +172,6 @@ enum cc_op { CC_OP_ADD_64, /* overflow on add (64bit) */ CC_OP_SUB_64, /* overflow on subtraction (64bit) */ - CC_OP_SUBU_64, /* overflow on unsigned subtraction (64bit) */ CC_OP_SUBB_64, /* overflow on unsigned sub-borrow (64bit) */ CC_OP_ABS_64, /* sign eval on abs (64bit) */ CC_OP_NABS_64, /* sign eval on nabs (64bit) */ @@ -179,7 +179,6 @@ enum cc_op { CC_OP_ADD_32, /* overflow on add (32bit) */ CC_OP_SUB_32, /* overflow on subtraction (32bit) */ - CC_OP_SUBU_32, /* overflow on unsigned subtraction (32bit) */ CC_OP_SUBB_32, /* overflow on unsigned sub-borrow (32bit) */ CC_OP_ABS_32, /* sign eval on abs (64bit) */ CC_OP_NABS_32, /* sign eval on nabs (64bit) */ |