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| author | Aurelien Jarno <aurelien@aurel32.net> | 2015-07-31 16:38:25 +0200 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2015-08-04 12:30:37 -0500 |
| commit | e750591c8abc0f68296f1afa9f3b9e678b4a28be (patch) | |
| tree | fe8bd6ab8dfe93d82ab13a10b5bbd858e45088f1 | |
| parent | f9c0ae272389b3581be13fe13986d7c509995be1 (diff) | |
| download | qemu-e750591c8abc0f68296f1afa9f3b9e678b4a28be.tar.gz | |
tcg/mips: fix add2
The add2 code in the tcg_out_addsub2 function doesn't take into account
the case where rl == al == bl. In that case we can't compute the carry
after the addition. As it corresponds to a multiplication by 2, the
carry bit is the bit 31.
While this is a corner case, this prevents x86-64 guests to boot on a
MIPS host.
Cc: qemu-stable@nongnu.org
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry picked from commit c99d69694af4ed15b33e3f7c2e3ef6972c14358d)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -rw-r--r-- | tcg/mips/tcg-target.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/tcg/mips/tcg-target.c b/tcg/mips/tcg-target.c index 6ca35a7d05..015ceab840 100644 --- a/tcg/mips/tcg-target.c +++ b/tcg/mips/tcg-target.c @@ -1269,6 +1269,9 @@ static void tcg_out_addsub2(TCGContext *s, TCGReg rl, TCGReg rh, TCGReg al, if (cbl) { tcg_out_opc_imm(s, OPC_ADDIU, rl, al, bl); tcg_out_opc_imm(s, OPC_SLTIU, TCG_TMP0, rl, bl); + } else if (rl == al && rl == bl) { + tcg_out_opc_sa(s, OPC_SRL, TCG_TMP0, al, 31); + tcg_out_opc_reg(s, OPC_ADDU, rl, al, bl); } else { tcg_out_opc_reg(s, OPC_ADDU, rl, al, bl); tcg_out_opc_reg(s, OPC_SLTU, TCG_TMP0, rl, (rl == bl ? al : bl)); |