diff options
Diffstat (limited to 'target/arm/vfp_helper.c')
| -rw-r--r-- | target/arm/vfp_helper.c | 374 |
1 files changed, 307 insertions, 67 deletions
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c index 3c8f3e6..5d42447 100644 --- a/target/arm/vfp_helper.c +++ b/target/arm/vfp_helper.c @@ -22,19 +22,63 @@ #include "exec/helper-proto.h" #include "internals.h" #include "cpu-features.h" +#include "fpu/softfloat.h" #ifdef CONFIG_TCG #include "qemu/log.h" -#include "fpu/softfloat.h" #endif /* VFP support. We follow the convention used for VFP instructions: Single precision routines have a "s" suffix, double precision a "d" suffix. */ +/* + * Set the float_status behaviour to match the Arm defaults: + * * tininess-before-rounding + * * 2-input NaN propagation prefers SNaN over QNaN, and then + * operand A over operand B (see FPProcessNaNs() pseudocode) + * * 3-input NaN propagation prefers SNaN over QNaN, and then + * operand C over A over B (see FPProcessNaNs3() pseudocode, + * but note that for QEMU muladd is a * b + c, whereas for + * the pseudocode function the arguments are in the order c, a, b. + * * 0 * Inf + NaN returns the default NaN if the input NaN is quiet, + * and the input NaN if it is signalling + * * Default NaN has sign bit clear, msb frac bit set + */ +void arm_set_default_fp_behaviours(float_status *s) +{ + set_float_detect_tininess(float_tininess_before_rounding, s); + set_float_ftz_detection(float_ftz_before_rounding, s); + set_float_2nan_prop_rule(float_2nan_prop_s_ab, s); + set_float_3nan_prop_rule(float_3nan_prop_s_cab, s); + set_float_infzeronan_rule(float_infzeronan_dnan_if_qnan, s); + set_float_default_nan_pattern(0b01000000, s); +} + +/* + * Set the float_status behaviour to match the FEAT_AFP + * FPCR.AH=1 requirements: + * * tininess-after-rounding + * * 2-input NaN propagation prefers the first NaN + * * 3-input NaN propagation prefers a over b over c + * * 0 * Inf + NaN always returns the input NaN and doesn't + * set Invalid for a QNaN + * * default NaN has sign bit set, msb frac bit set + */ +void arm_set_ah_fp_behaviours(float_status *s) +{ + set_float_detect_tininess(float_tininess_after_rounding, s); + set_float_ftz_detection(float_ftz_after_rounding, s); + set_float_2nan_prop_rule(float_2nan_prop_ab, s); + set_float_3nan_prop_rule(float_3nan_prop_abc, s); + set_float_infzeronan_rule(float_infzeronan_dnan_never | + float_infzeronan_suppress_invalid, s); + set_float_default_nan_pattern(0b11000000, s); +} + #ifdef CONFIG_TCG /* Convert host exception flags to vfp form. */ -static inline uint32_t vfp_exceptbits_from_host(int host_bits) +static inline uint32_t vfp_exceptbits_from_host(int host_bits, bool ah) { uint32_t target_bits = 0; @@ -56,24 +100,52 @@ static inline uint32_t vfp_exceptbits_from_host(int host_bits) if (host_bits & float_flag_input_denormal_flushed) { target_bits |= FPSR_IDC; } + /* + * With FPCR.AH, IDC is set when an input denormal is used, + * and flushing an output denormal to zero sets both IXC and UFC. + */ + if (ah && (host_bits & float_flag_input_denormal_used)) { + target_bits |= FPSR_IDC; + } + if (ah && (host_bits & float_flag_output_denormal_flushed)) { + target_bits |= FPSR_IXC; + } return target_bits; } static uint32_t vfp_get_fpsr_from_host(CPUARMState *env) { - uint32_t i = 0; + uint32_t a32_flags = 0, a64_flags = 0; - i |= get_float_exception_flags(&env->vfp.fp_status_a32); - i |= get_float_exception_flags(&env->vfp.fp_status_a64); - i |= get_float_exception_flags(&env->vfp.standard_fp_status); + a32_flags |= get_float_exception_flags(&env->vfp.fp_status[FPST_A32]); + a32_flags |= get_float_exception_flags(&env->vfp.fp_status[FPST_STD]); /* FZ16 does not generate an input denormal exception. */ - i |= (get_float_exception_flags(&env->vfp.fp_status_f16_a32) + a32_flags |= (get_float_exception_flags(&env->vfp.fp_status[FPST_A32_F16]) & ~float_flag_input_denormal_flushed); - i |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64) + a32_flags |= (get_float_exception_flags(&env->vfp.fp_status[FPST_STD_F16]) & ~float_flag_input_denormal_flushed); - i |= (get_float_exception_flags(&env->vfp.standard_fp_status_f16) - & ~float_flag_input_denormal_flushed); - return vfp_exceptbits_from_host(i); + + a64_flags |= get_float_exception_flags(&env->vfp.fp_status[FPST_A64]); + a64_flags |= (get_float_exception_flags(&env->vfp.fp_status[FPST_A64_F16]) + & ~(float_flag_input_denormal_flushed | float_flag_input_denormal_used)); + /* + * We do not merge in flags from FPST_AH or FPST_AH_F16, because + * they are used for insns that must not set the cumulative exception bits. + */ + + /* + * Flushing an input denormal *only* because FPCR.FIZ == 1 does + * not set FPSR.IDC; if FPCR.FZ is also set then this takes + * precedence and IDC is set (see the FPUnpackBase pseudocode). + * So squash it unless (FPCR.AH == 0 && FPCR.FZ == 1). + * We only do this for the a64 flags because FIZ has no effect + * on AArch32 even if it is set. + */ + if ((env->vfp.fpcr & (FPCR_FZ | FPCR_AH)) != FPCR_FZ) { + a64_flags &= ~float_flag_input_denormal_flushed; + } + return vfp_exceptbits_from_host(a64_flags, env->vfp.fpcr & FPCR_AH) | + vfp_exceptbits_from_host(a32_flags, false); } static void vfp_clear_float_status_exc_flags(CPUARMState *env) @@ -83,12 +155,25 @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env) * values. The caller should have arranged for env->vfp.fpsr to * be the architecturally up-to-date exception flag information first. */ - set_float_exception_flags(0, &env->vfp.fp_status_a32); - set_float_exception_flags(0, &env->vfp.fp_status_a64); - set_float_exception_flags(0, &env->vfp.fp_status_f16_a32); - set_float_exception_flags(0, &env->vfp.fp_status_f16_a64); - set_float_exception_flags(0, &env->vfp.standard_fp_status); - set_float_exception_flags(0, &env->vfp.standard_fp_status_f16); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_A32]); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_A64]); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_A32_F16]); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_A64_F16]); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD]); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD_F16]); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_AH]); + set_float_exception_flags(0, &env->vfp.fp_status[FPST_AH_F16]); +} + +static void vfp_sync_and_clear_float_status_exc_flags(CPUARMState *env) +{ + /* + * Synchronize any pending exception-flag information in the + * float_status values into env->vfp.fpsr, and then clear out + * the float_status data. + */ + env->vfp.fpsr |= vfp_get_fpsr_from_host(env); + vfp_clear_float_status_exc_flags(env); } static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask) @@ -113,33 +198,66 @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask) i = float_round_to_zero; break; } - set_float_rounding_mode(i, &env->vfp.fp_status_a32); - set_float_rounding_mode(i, &env->vfp.fp_status_a64); - set_float_rounding_mode(i, &env->vfp.fp_status_f16_a32); - set_float_rounding_mode(i, &env->vfp.fp_status_f16_a64); + set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A32]); + set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A64]); + set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A32_F16]); + set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A64_F16]); } if (changed & FPCR_FZ16) { bool ftz_enabled = val & FPCR_FZ16; - set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32); - set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64); - set_flush_to_zero(ftz_enabled, &env->vfp.standard_fp_status_f16); - set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32); - set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64); - set_flush_inputs_to_zero(ftz_enabled, &env->vfp.standard_fp_status_f16); + set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A32_F16]); + set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A64_F16]); + set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_STD_F16]); + set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_AH_F16]); + set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A32_F16]); + set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A64_F16]); + set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_STD_F16]); + set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_AH_F16]); } if (changed & FPCR_FZ) { bool ftz_enabled = val & FPCR_FZ; - set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_a32); - set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_a32); - set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_a64); - set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_a64); + set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A32]); + set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A64]); + /* FIZ is A64 only so FZ always makes A32 code flush inputs to zero */ + set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A32]); + } + if (changed & (FPCR_FZ | FPCR_AH | FPCR_FIZ)) { + /* + * A64: Flush denormalized inputs to zero if FPCR.FIZ = 1, or + * both FPCR.AH = 0 and FPCR.FZ = 1. + */ + bool fitz_enabled = (val & FPCR_FIZ) || + (val & (FPCR_FZ | FPCR_AH)) == FPCR_FZ; + set_flush_inputs_to_zero(fitz_enabled, &env->vfp.fp_status[FPST_A64]); } if (changed & FPCR_DN) { bool dnan_enabled = val & FPCR_DN; - set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_a32); - set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_a64); - set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a32); - set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a64); + set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A32]); + set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A64]); + set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A32_F16]); + set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A64_F16]); + set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_AH]); + set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_AH_F16]); + } + if (changed & FPCR_AH) { + bool ah_enabled = val & FPCR_AH; + + if (ah_enabled) { + /* Change behaviours for A64 FP operations */ + arm_set_ah_fp_behaviours(&env->vfp.fp_status[FPST_A64]); + arm_set_ah_fp_behaviours(&env->vfp.fp_status[FPST_A64_F16]); + } else { + arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_A64]); + arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_A64_F16]); + } + } + /* + * If any bits changed that we look at in vfp_get_fpsr_from_host(), + * we must sync the float_status flags into vfp.fpsr now (under the + * old regime) before we update vfp.fpcr. + */ + if (changed & (FPCR_FZ | FPCR_AH | FPCR_FIZ)) { + vfp_sync_and_clear_float_status_exc_flags(env); } } @@ -242,6 +360,9 @@ static void vfp_set_fpcr_masked(CPUARMState *env, uint32_t val, uint32_t mask) if (!cpu_isar_feature(any_fp16, cpu)) { val &= ~FPCR_FZ16; } + if (!cpu_isar_feature(aa64_afp, cpu)) { + val &= ~(FPCR_FIZ | FPCR_AH | FPCR_NEP); + } if (!cpu_isar_feature(aa64_ebf16, cpu)) { val &= ~FPCR_EBF; @@ -271,12 +392,14 @@ static void vfp_set_fpcr_masked(CPUARMState *env, uint32_t val, uint32_t mask) * We don't implement trapped exception handling, so the * trap enable bits, IDE|IXE|UFE|OFE|DZE|IOE are all RAZ/WI (not RES0!) * - * The FPCR bits we keep in vfp.fpcr are AHP, DN, FZ, RMode, EBF - * and FZ16. Len, Stride and LTPSIZE we just handled. Store those bits + * The FPCR bits we keep in vfp.fpcr are AHP, DN, FZ, RMode, EBF, FZ16, + * FIZ, AH, and NEP. + * Len, Stride and LTPSIZE we just handled. Store those bits * there, and zero any of the other FPCR bits and the RES0 and RAZ/WI * bits. */ - val &= FPCR_AHP | FPCR_DN | FPCR_FZ | FPCR_RMODE_MASK | FPCR_FZ16 | FPCR_EBF; + val &= FPCR_AHP | FPCR_DN | FPCR_FZ | FPCR_RMODE_MASK | FPCR_FZ16 | + FPCR_EBF | FPCR_FIZ | FPCR_AH | FPCR_NEP; env->vfp.fpcr &= ~mask; env->vfp.fpcr |= val; } @@ -366,16 +489,16 @@ static void softfloat_to_vfp_compare(CPUARMState *env, FloatRelation cmp) void VFP_HELPER(cmp, P)(ARGTYPE a, ARGTYPE b, CPUARMState *env) \ { \ softfloat_to_vfp_compare(env, \ - FLOATTYPE ## _compare_quiet(a, b, &env->vfp.FPST)); \ + FLOATTYPE ## _compare_quiet(a, b, &env->vfp.fp_status[FPST])); \ } \ void VFP_HELPER(cmpe, P)(ARGTYPE a, ARGTYPE b, CPUARMState *env) \ { \ softfloat_to_vfp_compare(env, \ - FLOATTYPE ## _compare(a, b, &env->vfp.FPST)); \ + FLOATTYPE ## _compare(a, b, &env->vfp.fp_status[FPST])); \ } -DO_VFP_cmp(h, float16, dh_ctype_f16, fp_status_f16_a32) -DO_VFP_cmp(s, float32, float32, fp_status_a32) -DO_VFP_cmp(d, float64, float64, fp_status_a32) +DO_VFP_cmp(h, float16, dh_ctype_f16, FPST_A32_F16) +DO_VFP_cmp(s, float32, float32, FPST_A32) +DO_VFP_cmp(d, float64, float64, FPST_A32) #undef DO_VFP_cmp /* Integer to float and float to integer conversions */ @@ -611,6 +734,33 @@ static int recip_estimate(int input) } /* + * Increased precision version: + * input is a 13 bit fixed point number + * input range 2048 .. 4095 for a number from 0.5 <= x < 1.0. + * result range 4096 .. 8191 for a number from 1.0 to 2.0 + */ +static int recip_estimate_incprec(int input) +{ + int a, b, r; + assert(2048 <= input && input < 4096); + a = (input * 2) + 1; + /* + * The pseudocode expresses this as an operation on infinite + * precision reals where it calculates 2^25 / a and then looks + * at the error between that and the rounded-down-to-integer + * value to see if it should instead round up. We instead + * follow the same approach as the pseudocode for the 8-bit + * precision version, and calculate (2 * (2^25 / a)) as an + * integer so we can do the "add one and halve" to round it. + * So the 1 << 26 here is correct. + */ + b = (1 << 26) / a; + r = (b + 1) >> 1; + assert(4096 <= r && r < 8192); + return r; +} + +/* * Common wrapper to call recip_estimate * * The parameters are exponent and 64 bit fraction (without implicit @@ -619,7 +769,8 @@ static int recip_estimate(int input) * callee. */ -static uint64_t call_recip_estimate(int *exp, int exp_off, uint64_t frac) +static uint64_t call_recip_estimate(int *exp, int exp_off, uint64_t frac, + bool increasedprecision) { uint32_t scaled, estimate; uint64_t result_frac; @@ -635,12 +786,22 @@ static uint64_t call_recip_estimate(int *exp, int exp_off, uint64_t frac) } } - /* scaled = UInt('1':fraction<51:44>) */ - scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8)); - estimate = recip_estimate(scaled); + if (increasedprecision) { + /* scaled = UInt('1':fraction<51:41>) */ + scaled = deposit32(1 << 11, 0, 11, extract64(frac, 41, 11)); + estimate = recip_estimate_incprec(scaled); + } else { + /* scaled = UInt('1':fraction<51:44>) */ + scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8)); + estimate = recip_estimate(scaled); + } result_exp = exp_off - *exp; - result_frac = deposit64(0, 44, 8, estimate); + if (increasedprecision) { + result_frac = deposit64(0, 40, 12, estimate); + } else { + result_frac = deposit64(0, 44, 8, estimate); + } if (result_exp == 0) { result_frac = deposit64(result_frac >> 1, 51, 1, 1); } else if (result_exp == -1) { @@ -709,7 +870,7 @@ uint32_t HELPER(recpe_f16)(uint32_t input, float_status *fpst) } f64_frac = call_recip_estimate(&f16_exp, 29, - ((uint64_t) f16_frac) << (52 - 10)); + ((uint64_t) f16_frac) << (52 - 10), false); /* result = sign : result_exp<4:0> : fraction<51:42> */ f16_val = deposit32(0, 15, 1, f16_sign); @@ -718,7 +879,11 @@ uint32_t HELPER(recpe_f16)(uint32_t input, float_status *fpst) return make_float16(f16_val); } -float32 HELPER(recpe_f32)(float32 input, float_status *fpst) +/* + * FEAT_RPRES means the f32 FRECPE has an "increased precision" variant + * which is used when FPCR.AH == 1. + */ +static float32 do_recpe_f32(float32 input, float_status *fpst, bool rpres) { float32 f32 = float32_squash_input_denormal(input, fpst); uint32_t f32_val = float32_val(f32); @@ -758,7 +923,7 @@ float32 HELPER(recpe_f32)(float32 input, float_status *fpst) } f64_frac = call_recip_estimate(&f32_exp, 253, - ((uint64_t) f32_frac) << (52 - 23)); + ((uint64_t) f32_frac) << (52 - 23), rpres); /* result = sign : result_exp<7:0> : fraction<51:29> */ f32_val = deposit32(0, 31, 1, f32_sign); @@ -767,6 +932,16 @@ float32 HELPER(recpe_f32)(float32 input, float_status *fpst) return make_float32(f32_val); } +float32 HELPER(recpe_f32)(float32 input, float_status *fpst) +{ + return do_recpe_f32(input, fpst, false); +} + +float32 HELPER(recpe_rpres_f32)(float32 input, float_status *fpst) +{ + return do_recpe_f32(input, fpst, true); +} + float64 HELPER(recpe_f64)(float64 input, float_status *fpst) { float64 f64 = float64_squash_input_denormal(input, fpst); @@ -806,7 +981,7 @@ float64 HELPER(recpe_f64)(float64 input, float_status *fpst) return float64_set_sign(float64_zero, float64_is_neg(f64)); } - f64_frac = call_recip_estimate(&f64_exp, 2045, f64_frac); + f64_frac = call_recip_estimate(&f64_exp, 2045, f64_frac, false); /* result = sign : result_exp<10:0> : fraction<51:0>; */ f64_val = deposit64(0, 63, 1, f64_sign); @@ -840,8 +1015,36 @@ static int do_recip_sqrt_estimate(int a) return estimate; } +static int do_recip_sqrt_estimate_incprec(int a) +{ + /* + * The Arm ARM describes the 12-bit precision version of RecipSqrtEstimate + * in terms of an infinite-precision floating point calculation of a + * square root. We implement this using the same kind of pure integer + * algorithm as the 8-bit mantissa, to get the same bit-for-bit result. + */ + int64_t b, estimate; + + assert(1024 <= a && a < 4096); + if (a < 2048) { + a = a * 2 + 1; + } else { + a = (a >> 1) << 1; + a = (a + 1) * 2; + } + b = 8192; + while (a * (b + 1) * (b + 1) < (1ULL << 39)) { + b += 1; + } + estimate = (b + 1) / 2; + + assert(4096 <= estimate && estimate < 8192); -static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac) + return estimate; +} + +static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac, + bool increasedprecision) { int estimate; uint32_t scaled; @@ -854,17 +1057,32 @@ static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac) frac = extract64(frac, 0, 51) << 1; } - if (*exp & 1) { - /* scaled = UInt('01':fraction<51:45>) */ - scaled = deposit32(1 << 7, 0, 7, extract64(frac, 45, 7)); + if (increasedprecision) { + if (*exp & 1) { + /* scaled = UInt('01':fraction<51:42>) */ + scaled = deposit32(1 << 10, 0, 10, extract64(frac, 42, 10)); + } else { + /* scaled = UInt('1':fraction<51:41>) */ + scaled = deposit32(1 << 11, 0, 11, extract64(frac, 41, 11)); + } + estimate = do_recip_sqrt_estimate_incprec(scaled); } else { - /* scaled = UInt('1':fraction<51:44>) */ - scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8)); + if (*exp & 1) { + /* scaled = UInt('01':fraction<51:45>) */ + scaled = deposit32(1 << 7, 0, 7, extract64(frac, 45, 7)); + } else { + /* scaled = UInt('1':fraction<51:44>) */ + scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8)); + } + estimate = do_recip_sqrt_estimate(scaled); } - estimate = do_recip_sqrt_estimate(scaled); *exp = (exp_off - *exp) / 2; - return extract64(estimate, 0, 8) << 44; + if (increasedprecision) { + return extract64(estimate, 0, 12) << 40; + } else { + return extract64(estimate, 0, 8) << 44; + } } uint32_t HELPER(rsqrte_f16)(uint32_t input, float_status *s) @@ -903,7 +1121,7 @@ uint32_t HELPER(rsqrte_f16)(uint32_t input, float_status *s) f64_frac = ((uint64_t) f16_frac) << (52 - 10); - f64_frac = recip_sqrt_estimate(&f16_exp, 44, f64_frac); + f64_frac = recip_sqrt_estimate(&f16_exp, 44, f64_frac, false); /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(2) */ val = deposit32(0, 15, 1, f16_sign); @@ -912,7 +1130,11 @@ uint32_t HELPER(rsqrte_f16)(uint32_t input, float_status *s) return make_float16(val); } -float32 HELPER(rsqrte_f32)(float32 input, float_status *s) +/* + * FEAT_RPRES means the f32 FRSQRTE has an "increased precision" variant + * which is used when FPCR.AH == 1. + */ +static float32 do_rsqrte_f32(float32 input, float_status *s, bool rpres) { float32 f32 = float32_squash_input_denormal(input, s); uint32_t val = float32_val(f32); @@ -948,15 +1170,33 @@ float32 HELPER(rsqrte_f32)(float32 input, float_status *s) f64_frac = ((uint64_t) f32_frac) << 29; - f64_frac = recip_sqrt_estimate(&f32_exp, 380, f64_frac); + f64_frac = recip_sqrt_estimate(&f32_exp, 380, f64_frac, rpres); - /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(15) */ + /* + * result = sign : result_exp<7:0> : estimate<7:0> : Zeros(15) + * or for increased precision + * result = sign : result_exp<7:0> : estimate<11:0> : Zeros(11) + */ val = deposit32(0, 31, 1, f32_sign); val = deposit32(val, 23, 8, f32_exp); - val = deposit32(val, 15, 8, extract64(f64_frac, 52 - 8, 8)); + if (rpres) { + val = deposit32(val, 11, 12, extract64(f64_frac, 52 - 12, 12)); + } else { + val = deposit32(val, 15, 8, extract64(f64_frac, 52 - 8, 8)); + } return make_float32(val); } +float32 HELPER(rsqrte_f32)(float32 input, float_status *s) +{ + return do_rsqrte_f32(input, s, false); +} + +float32 HELPER(rsqrte_rpres_f32)(float32 input, float_status *s) +{ + return do_rsqrte_f32(input, s, true); +} + float64 HELPER(rsqrte_f64)(float64 input, float_status *s) { float64 f64 = float64_squash_input_denormal(input, s); @@ -987,7 +1227,7 @@ float64 HELPER(rsqrte_f64)(float64 input, float_status *s) return float64_zero; } - f64_frac = recip_sqrt_estimate(&f64_exp, 3068, f64_frac); + f64_frac = recip_sqrt_estimate(&f64_exp, 3068, f64_frac, false); /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(44) */ val = deposit64(0, 61, 1, f64_sign); @@ -1145,7 +1385,7 @@ uint64_t HELPER(fjcvtzs)(float64 value, float_status *status) uint32_t HELPER(vjcvt)(float64 value, CPUARMState *env) { - uint64_t pair = HELPER(fjcvtzs)(value, &env->vfp.fp_status_a32); + uint64_t pair = HELPER(fjcvtzs)(value, &env->vfp.fp_status[FPST_A32]); uint32_t result = pair; uint32_t z = (pair >> 32) == 0; |