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Re: [Qemu-devel] [PATCH 21/38] target-arm: Implement sbc_cc inline
From: |
Peter Crosthwaite |
Subject: |
Re: [Qemu-devel] [PATCH 21/38] target-arm: Implement sbc_cc inline |
Date: |
Mon, 25 Feb 2013 17:43:39 +1000 |
Hi All,
Same problem as commented on patch 20.
On Wed, Feb 20, 2013 at 5:52 PM, Richard Henderson <address@hidden> wrote:
> Use sub2 if available, otherwise use 64-bit arithmetic.
>
> Cc: Peter Maydell <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> target-arm/helper.h | 2 --
> target-arm/op_helper.c | 15 ---------------
> target-arm/translate.c | 47 +++++++++++++++++++++++++++++++++++++++--------
> 3 files changed, 39 insertions(+), 25 deletions(-)
>
> diff --git a/target-arm/helper.h b/target-arm/helper.h
> index 507bb9c..63ae13a 100644
> --- a/target-arm/helper.h
> +++ b/target-arm/helper.h
> @@ -140,8 +140,6 @@ DEF_HELPER_2(recpe_u32, i32, i32, env)
> DEF_HELPER_2(rsqrte_u32, i32, i32, env)
> DEF_HELPER_5(neon_tbl, i32, env, i32, i32, i32, i32)
>
> -DEF_HELPER_3(sbc_cc, i32, env, i32, i32)
> -
> DEF_HELPER_3(shl_cc, i32, env, i32, i32)
> DEF_HELPER_3(shr_cc, i32, env, i32, i32)
> DEF_HELPER_3(sar_cc, i32, env, i32, i32)
> diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
> index 49fc036..a522313 100644
> --- a/target-arm/op_helper.c
> +++ b/target-arm/op_helper.c
> @@ -315,21 +315,6 @@ uint64_t HELPER(get_cp_reg64)(CPUARMState *env, void
> *rip)
> The only way to do that in TCG is a conditional branch, which clobbers
> all our temporaries. For now implement these as helper functions. */
>
> -uint32_t HELPER(sbc_cc)(CPUARMState *env, uint32_t a, uint32_t b)
> -{
> - uint32_t result;
> - if (!env->CF) {
> - result = a - b - 1;
> - env->CF = a > b;
> - } else {
> - result = a - b;
> - env->CF = a >= b;
> - }
> - env->VF = (a ^ b) & (a ^ result);
> - env->NF = env->ZF = result;
> - return result;
> -}
> -
> /* Similarly for variable shift instructions. */
>
> uint32_t HELPER(shl_cc)(CPUARMState *env, uint32_t x, uint32_t i)
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index 493448a..9993aea 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -464,6 +464,35 @@ 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 */
> +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);
Discards NF intermediary result and re-uses operand t0.
Regard,
Peter
> + tcg_gen_sub2_i32(cpu_NF, cpu_CF, t0, 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);
> +}
> +
> #define GEN_SHIFT(name) \
> static void gen_##name(TCGv dest, TCGv t0, TCGv t1) \
> { \
> @@ -7109,7 +7138,7 @@ static void disas_arm_insn(CPUARMState * env,
> DisasContext *s)
> break;
> case 0x06:
> if (set_cc) {
> - gen_helper_sbc_cc(tmp, cpu_env, tmp, tmp2);
> + gen_sbc_CC(tmp, tmp, tmp2);
> } else {
> gen_sub_carry(tmp, tmp, tmp2);
> }
> @@ -7117,7 +7146,7 @@ static void disas_arm_insn(CPUARMState * env,
> DisasContext *s)
> break;
> case 0x07:
> if (set_cc) {
> - gen_helper_sbc_cc(tmp, cpu_env, tmp2, tmp);
> + gen_sbc_CC(tmp, tmp2, tmp);
> } else {
> gen_sub_carry(tmp, tmp2, tmp);
> }
> @@ -7947,10 +7976,11 @@ gen_thumb2_data_op(DisasContext *s, int op, int
> conds, uint32_t shifter_out, TCG
> gen_adc(t0, t1);
> break;
> case 11: /* sbc */
> - if (conds)
> - gen_helper_sbc_cc(t0, cpu_env, t0, t1);
> - else
> + if (conds) {
> + gen_sbc_CC(t0, t0, t1);
> + } else {
> gen_sub_carry(t0, t0, t1);
> + }
> break;
> case 13: /* sub */
> if (conds)
> @@ -9267,10 +9297,11 @@ static void disas_thumb_insn(CPUARMState *env,
> DisasContext *s)
> }
> break;
> case 0x6: /* sbc */
> - if (s->condexec_mask)
> + if (s->condexec_mask) {
> gen_sub_carry(tmp, tmp, tmp2);
> - else
> - gen_helper_sbc_cc(tmp, cpu_env, tmp, tmp2);
> + } else {
> + gen_sbc_CC(tmp, tmp, tmp2);
> + }
> break;
> case 0x7: /* ror */
> if (s->condexec_mask) {
> --
> 1.8.1.2
>
>
- [Qemu-devel] [PATCH 29/38] target-ppc: Use add2 for carry generation, (continued)
- [Qemu-devel] [PATCH 29/38] target-ppc: Use add2 for carry generation, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 19/38] target-arm: Use add2 in gen_add_CC, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 27/38] target-ppc: Compute addition overflow without branches, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 22/38] target-mips: Use mul[us]2 in [D]MULT[U] insns, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 23/38] target-cris: Use mul*2 in mul* insns, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 25/38] target-ppc: Split out SO, OV, CA fields from XER, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 17/38] target-arm: Use mul[us]2 in gen_mul[us]_i64_i32, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 38/38] target-xtensa: Use add2/sub2 for mac, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 26/38] target-ppc: Use setcond in gen_op_cmp, Richard Henderson, 2013/02/20
- [Qemu-devel] [PATCH 21/38] target-arm: Implement sbc_cc inline, Richard Henderson, 2013/02/20
- Re: [Qemu-devel] [PATCH 21/38] target-arm: Implement sbc_cc inline,
Peter Crosthwaite <=
- Re: [Qemu-devel] [PATCH 00/38] Add double-word addition and widening multiply tcg ops, Blue Swirl, 2013/02/23
- Re: [Qemu-devel] [PATCH 00/38] Add double-word addition and widening multiply tcg ops, Alexander Graf, 2013/02/25