diff options
| author | Richard Henderson <rth@twiddle.net> | 2013-02-25 11:41:39 -0800 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2013-02-25 14:32:36 -0600 |
| commit | e77f083292916ba43b940fdacd2fc1001b750d1d (patch) | |
| tree | ac7fd7f25acb15e0f1d182130d8df59ff417dfd9 /target-arm/translate.c | |
| parent | 8c3ac601bdaf8d4d81823a79f2a166b586db7dab (diff) | |
| download | qemu-e77f083292916ba43b940fdacd2fc1001b750d1d.zip | |
target-arm: Fix sbc_CC carry
While T0+~T1+CF = T0-T1+CF-1 is true for the low 32-bits,
it does not produce the correct carry-out to bit 33. Do
exactly what the manual says.
Using the ~T1 makes the add and subtract code paths nearly
identical, so have sbc_CC use adc_CC.
Cc: Peter Maydell <peter.maydell@linaro.org>
Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'target-arm/translate.c')
| -rw-r--r-- | target-arm/translate.c | 28 |
1 files changed, 4 insertions, 24 deletions
diff --git a/target-arm/translate.c b/target-arm/translate.c index 6d91b70aff..f2f649dffd 100644 --- a/target-arm/translate.c +++ b/target-arm/translate.c @@ -464,33 +464,13 @@ static void gen_sub_CC(TCGv dest, TCGv t0, TCGv t1) tcg_gen_mov_i32(dest, cpu_NF); } -/* dest = T0 + ~T1 + CF = T0 - T1 + CF - 1. Compute C, N, V and Z flags */ +/* dest = T0 + ~T1 + CF. Compute C, N, V and Z flags */ static void gen_sbc_CC(TCGv dest, TCGv t0, TCGv t1) { TCGv tmp = tcg_temp_new_i32(); - tcg_gen_subi_i32(cpu_CF, cpu_CF, 1); - if (TCG_TARGET_HAS_add2_i32) { - tcg_gen_movi_i32(tmp, 0); - tcg_gen_add2_i32(cpu_NF, cpu_CF, t0, tmp, cpu_CF, tmp); - tcg_gen_sub2_i32(cpu_NF, cpu_CF, cpu_NF, cpu_CF, t1, tmp); - } else { - TCGv_i64 q0 = tcg_temp_new_i64(); - TCGv_i64 q1 = tcg_temp_new_i64(); - tcg_gen_extu_i32_i64(q0, t0); - tcg_gen_extu_i32_i64(q1, t1); - tcg_gen_sub_i64(q0, q0, q1); - tcg_gen_extu_i32_i64(q1, cpu_CF); - tcg_gen_add_i64(q0, q0, q1); - tcg_gen_extr_i64_i32(cpu_NF, cpu_CF, q0); - tcg_temp_free_i64(q0); - tcg_temp_free_i64(q1); - } - tcg_gen_mov_i32(cpu_ZF, cpu_NF); - tcg_gen_xor_i32(cpu_VF, cpu_NF, t0); - tcg_gen_xor_i32(tmp, t0, t1); - tcg_gen_and_i32(cpu_VF, cpu_VF, tmp); - tcg_temp_free_i32(tmp); - tcg_gen_mov_i32(dest, cpu_NF); + tcg_gen_not_i32(tmp, t1); + gen_adc_CC(dest, t0, tmp); + tcg_temp_free(tmp); } #define GEN_SHIFT(name) \ |