diff options
Diffstat (limited to 'target/arm/vfp_helper.c')
| -rw-r--r-- | target/arm/vfp_helper.c | 76 |
1 files changed, 56 insertions, 20 deletions
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c index 5666393ef7..01b9d8557f 100644 --- a/target/arm/vfp_helper.c +++ b/target/arm/vfp_helper.c @@ -174,6 +174,12 @@ uint32_t HELPER(vfp_get_fpscr)(CPUARMState *env) | (env->vfp.vec_len << 16) | (env->vfp.vec_stride << 20); + /* + * M-profile LTPSIZE overlaps A-profile Stride; whichever of the + * two is not applicable to this CPU will always be zero. + */ + fpscr |= env->v7m.ltpsize << 16; + fpscr |= vfp_get_fpscr_from_host(env); i = env->vfp.qc[0] | env->vfp.qc[1] | env->vfp.qc[2] | env->vfp.qc[3]; @@ -194,36 +200,45 @@ void HELPER(vfp_set_fpscr)(CPUARMState *env, uint32_t val) val &= ~FPCR_FZ16; } - if (arm_feature(env, ARM_FEATURE_M)) { + vfp_set_fpscr_to_host(env, val); + + if (!arm_feature(env, ARM_FEATURE_M)) { /* - * M profile FPSCR is RES0 for the QC, STRIDE, FZ16, LEN bits - * and also for the trapped-exception-handling bits IxE. + * Short-vector length and stride; on M-profile these bits + * are used for different purposes. + * We can't make this conditional be "if MVFR0.FPShVec != 0", + * because in v7A no-short-vector-support cores still had to + * allow Stride/Len to be written with the only effect that + * some insns are required to UNDEF if the guest sets them. + * + * TODO: if M-profile MVE implemented, set LTPSIZE. */ - val &= 0xf7c0009f; + env->vfp.vec_len = extract32(val, 16, 3); + env->vfp.vec_stride = extract32(val, 20, 2); } - vfp_set_fpscr_to_host(env, val); + if (arm_feature(env, ARM_FEATURE_NEON)) { + /* + * The bit we set within fpscr_q is arbitrary; the register as a + * whole being zero/non-zero is what counts. + * TODO: M-profile MVE also has a QC bit. + */ + env->vfp.qc[0] = val & FPCR_QC; + env->vfp.qc[1] = 0; + env->vfp.qc[2] = 0; + env->vfp.qc[3] = 0; + } /* * We don't implement trapped exception handling, so the * trap enable bits, IDE|IXE|UFE|OFE|DZE|IOE are all RAZ/WI (not RES0!) * - * If we exclude the exception flags, IOC|DZC|OFC|UFC|IXC|IDC - * (which are stored in fp_status), and the other RES0 bits - * in between, then we clear all of the low 16 bits. + * The exception flags IOC|DZC|OFC|UFC|IXC|IDC are stored in + * fp_status; QC, Len and Stride are stored separately earlier. + * Clear out all of those and the RES0 bits: only NZCV, AHP, DN, + * FZ, RMode and FZ16 are kept in vfp.xregs[FPSCR]. */ env->vfp.xregs[ARM_VFP_FPSCR] = val & 0xf7c80000; - env->vfp.vec_len = (val >> 16) & 7; - env->vfp.vec_stride = (val >> 20) & 3; - - /* - * The bit we set within fpscr_q is arbitrary; the register as a - * whole being zero/non-zero is what counts. - */ - env->vfp.qc[0] = val & FPCR_QC; - env->vfp.qc[1] = 0; - env->vfp.qc[2] = 0; - env->vfp.qc[3] = 0; } void vfp_set_fpscr(CPUARMState *env, uint32_t val) @@ -393,12 +408,32 @@ float32 VFP_HELPER(fcvts, d)(float64 x, CPUARMState *env) return float64_to_float32(x, &env->vfp.fp_status); } -/* VFP3 fixed point conversion. */ +/* + * VFP3 fixed point conversion. The AArch32 versions of fix-to-float + * must always round-to-nearest; the AArch64 ones honour the FPSCR + * rounding mode. (For AArch32 Neon the standard-FPSCR is set to + * round-to-nearest so either helper will work.) AArch32 float-to-fix + * must round-to-zero. + */ #define VFP_CONV_FIX_FLOAT(name, p, fsz, ftype, isz, itype) \ ftype HELPER(vfp_##name##to##p)(uint##isz##_t x, uint32_t shift, \ void *fpstp) \ { return itype##_to_##float##fsz##_scalbn(x, -shift, fpstp); } +#define VFP_CONV_FIX_FLOAT_ROUND(name, p, fsz, ftype, isz, itype) \ + ftype HELPER(vfp_##name##to##p##_round_to_nearest)(uint##isz##_t x, \ + uint32_t shift, \ + void *fpstp) \ + { \ + ftype ret; \ + float_status *fpst = fpstp; \ + FloatRoundMode oldmode = fpst->float_rounding_mode; \ + fpst->float_rounding_mode = float_round_nearest_even; \ + ret = itype##_to_##float##fsz##_scalbn(x, -shift, fpstp); \ + fpst->float_rounding_mode = oldmode; \ + return ret; \ + } + #define VFP_CONV_FLOAT_FIX_ROUND(name, p, fsz, ftype, isz, itype, ROUND, suff) \ uint##isz##_t HELPER(vfp_to##name##p##suff)(ftype x, uint32_t shift, \ void *fpst) \ @@ -412,6 +447,7 @@ uint##isz##_t HELPER(vfp_to##name##p##suff)(ftype x, uint32_t shift, \ #define VFP_CONV_FIX(name, p, fsz, ftype, isz, itype) \ VFP_CONV_FIX_FLOAT(name, p, fsz, ftype, isz, itype) \ +VFP_CONV_FIX_FLOAT_ROUND(name, p, fsz, ftype, isz, itype) \ VFP_CONV_FLOAT_FIX_ROUND(name, p, fsz, ftype, isz, itype, \ float_round_to_zero, _round_to_zero) \ VFP_CONV_FLOAT_FIX_ROUND(name, p, fsz, ftype, isz, itype, \ |