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target-arm: UNDEF on a VCVTT/VCVTB UNPREDICTABLE to avoid TCG assert

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VCVTT/VCVTB with bit 8 set is UNPREDICTABLE; we choose to UNDEF.
This avoids a TCG assert later when the VCVTT/VCVTB code tries to
use a source register that wasn't ever set up.

We pull the check for the presence of the half-precision extension
up in to this common code as well.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell 2011-07-22 00:51:20 +00:00
parent 934814f198
commit 6e0c0ed185
1 changed files with 11 additions and 8 deletions
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19
target-arm/translate.c
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@ -3071,6 +3071,17 @@ static int disas_vfp_insn(CPUState * env, DisasContext *s, uint32_t insn)
/* Source and destination the same. */
gen_mov_F0_vreg(dp, rd);
break;
case 4:
case 5:
case 6:
case 7:
/* VCVTB, VCVTT: only present with the halfprec extension,
* UNPREDICTABLE if bit 8 is set (we choose to UNDEF)
*/
if (dp || !arm_feature(env, ARM_FEATURE_VFP_FP16)) {
return 1;
}
/* Otherwise fall through */
default:
/* One source operand. */
gen_mov_F0_vreg(dp, rm);
@ -3167,24 +3178,18 @@ static int disas_vfp_insn(CPUState * env, DisasContext *s, uint32_t insn)
gen_vfp_sqrt(dp);
break;
case 4: /* vcvtb.f32.f16 */
if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
return 1;
tmp = gen_vfp_mrs();
tcg_gen_ext16u_i32(tmp, tmp);
gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp, cpu_env);
tcg_temp_free_i32(tmp);
break;
case 5: /* vcvtt.f32.f16 */
if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
return 1;
tmp = gen_vfp_mrs();
tcg_gen_shri_i32(tmp, tmp, 16);
gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp, cpu_env);
tcg_temp_free_i32(tmp);
break;
case 6: /* vcvtb.f16.f32 */
if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
return 1;
tmp = tcg_temp_new_i32();
gen_helper_vfp_fcvt_f32_to_f16(tmp, cpu_F0s, cpu_env);
gen_mov_F0_vreg(0, rd);
@ -3195,8 +3200,6 @@ static int disas_vfp_insn(CPUState * env, DisasContext *s, uint32_t insn)
gen_vfp_msr(tmp);
break;
case 7: /* vcvtt.f16.f32 */
if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
return 1;
tmp = tcg_temp_new_i32();
gen_helper_vfp_fcvt_f32_to_f16(tmp, cpu_F0s, cpu_env);
tcg_gen_shli_i32(tmp, tmp, 16);