From e77f083292916ba43b940fdacd2fc1001b750d1d Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 25 Feb 2013 11:41:39 -0800 Subject: [PATCH] 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 Reported-by: Laurent Desnogues Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson Signed-off-by: Anthony Liguori --- target-arm/translate.c | 28 ++++------------------------ 1 file 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) \