diff options
Diffstat (limited to 'target/alpha/fpu_helper.c')
| -rw-r--r-- | target/alpha/fpu_helper.c | 553 |
1 files changed, 553 insertions, 0 deletions
diff --git a/target/alpha/fpu_helper.c b/target/alpha/fpu_helper.c new file mode 100644 index 0000000000..9645978aaa --- /dev/null +++ b/target/alpha/fpu_helper.c @@ -0,0 +1,553 @@ +/* + * Helpers for floating point instructions. + * + * Copyright (c) 2007 Jocelyn Mayer + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ + +#include "qemu/osdep.h" +#include "cpu.h" +#include "exec/exec-all.h" +#include "exec/helper-proto.h" +#include "fpu/softfloat.h" + +#define FP_STATUS (env->fp_status) + + +void helper_setroundmode(CPUAlphaState *env, uint32_t val) +{ + set_float_rounding_mode(val, &FP_STATUS); +} + +void helper_setflushzero(CPUAlphaState *env, uint32_t val) +{ + set_flush_to_zero(val, &FP_STATUS); +} + +#define CONVERT_BIT(X, SRC, DST) \ + (SRC > DST ? (X) / (SRC / DST) & (DST) : ((X) & SRC) * (DST / SRC)) + +static uint32_t soft_to_fpcr_exc(CPUAlphaState *env) +{ + uint8_t exc = get_float_exception_flags(&FP_STATUS); + uint32_t ret = 0; + + if (unlikely(exc)) { + set_float_exception_flags(0, &FP_STATUS); + ret |= CONVERT_BIT(exc, float_flag_invalid, FPCR_INV); + ret |= CONVERT_BIT(exc, float_flag_divbyzero, FPCR_DZE); + ret |= CONVERT_BIT(exc, float_flag_overflow, FPCR_OVF); + ret |= CONVERT_BIT(exc, float_flag_underflow, FPCR_UNF); + ret |= CONVERT_BIT(exc, float_flag_inexact, FPCR_INE); + } + + return ret; +} + +static void fp_exc_raise1(CPUAlphaState *env, uintptr_t retaddr, + uint32_t exc, uint32_t regno, uint32_t hw_exc) +{ + hw_exc |= CONVERT_BIT(exc, FPCR_INV, EXC_M_INV); + hw_exc |= CONVERT_BIT(exc, FPCR_DZE, EXC_M_DZE); + hw_exc |= CONVERT_BIT(exc, FPCR_OVF, EXC_M_FOV); + hw_exc |= CONVERT_BIT(exc, FPCR_UNF, EXC_M_UNF); + hw_exc |= CONVERT_BIT(exc, FPCR_INE, EXC_M_INE); + hw_exc |= CONVERT_BIT(exc, FPCR_IOV, EXC_M_IOV); + + arith_excp(env, retaddr, hw_exc, 1ull << regno); +} + +/* Raise exceptions for ieee fp insns without software completion. + In that case there are no exceptions that don't trap; the mask + doesn't apply. */ +void helper_fp_exc_raise(CPUAlphaState *env, uint32_t ignore, uint32_t regno) +{ + uint32_t exc = env->error_code; + if (exc) { + env->fpcr |= exc; + exc &= ~ignore; + if (exc) { + fp_exc_raise1(env, GETPC(), exc, regno, 0); + } + } +} + +/* Raise exceptions for ieee fp insns with software completion. */ +void helper_fp_exc_raise_s(CPUAlphaState *env, uint32_t ignore, uint32_t regno) +{ + uint32_t exc = env->error_code & ~ignore; + if (exc) { + env->fpcr |= exc; + exc &= ~ignore; + if (exc) { + exc &= env->fpcr_exc_enable; + fp_exc_raise1(env, GETPC(), exc, regno, EXC_M_SWC); + } + } +} + +/* Input handing without software completion. Trap for all + non-finite numbers. */ +void helper_ieee_input(CPUAlphaState *env, uint64_t val) +{ + uint32_t exp = (uint32_t)(val >> 52) & 0x7ff; + uint64_t frac = val & 0xfffffffffffffull; + + if (exp == 0) { + /* Denormals without /S raise an exception. */ + if (frac != 0) { + arith_excp(env, GETPC(), EXC_M_INV, 0); + } + } else if (exp == 0x7ff) { + /* Infinity or NaN. */ + env->fpcr |= FPCR_INV; + arith_excp(env, GETPC(), EXC_M_INV, 0); + } +} + +/* Similar, but does not trap for infinities. Used for comparisons. */ +void helper_ieee_input_cmp(CPUAlphaState *env, uint64_t val) +{ + uint32_t exp = (uint32_t)(val >> 52) & 0x7ff; + uint64_t frac = val & 0xfffffffffffffull; + + if (exp == 0) { + /* Denormals without /S raise an exception. */ + if (frac != 0) { + arith_excp(env, GETPC(), EXC_M_INV, 0); + } + } else if (exp == 0x7ff && frac) { + /* NaN. */ + env->fpcr |= FPCR_INV; + arith_excp(env, GETPC(), EXC_M_INV, 0); + } +} + +/* Input handing with software completion. Trap for denorms, unless DNZ + is set. If we try to support DNOD (which none of the produced hardware + did, AFAICS), we'll need to suppress the trap when FPCR.DNOD is set; + then the code downstream of that will need to cope with denorms sans + flush_input_to_zero. Most of it should work sanely, but there's + nothing to compare with. */ +void helper_ieee_input_s(CPUAlphaState *env, uint64_t val) +{ + if (unlikely(2 * val - 1 < 0x1fffffffffffffull) + && !env->fp_status.flush_inputs_to_zero) { + arith_excp(env, GETPC(), EXC_M_INV | EXC_M_SWC, 0); + } +} + +/* S floating (single) */ + +/* Taken from linux/arch/alpha/kernel/traps.c, s_mem_to_reg. */ +static inline uint64_t float32_to_s_int(uint32_t fi) +{ + uint32_t frac = fi & 0x7fffff; + uint32_t sign = fi >> 31; + uint32_t exp_msb = (fi >> 30) & 1; + uint32_t exp_low = (fi >> 23) & 0x7f; + uint32_t exp; + + exp = (exp_msb << 10) | exp_low; + if (exp_msb) { + if (exp_low == 0x7f) { + exp = 0x7ff; + } + } else { + if (exp_low != 0x00) { + exp |= 0x380; + } + } + + return (((uint64_t)sign << 63) + | ((uint64_t)exp << 52) + | ((uint64_t)frac << 29)); +} + +static inline uint64_t float32_to_s(float32 fa) +{ + CPU_FloatU a; + a.f = fa; + return float32_to_s_int(a.l); +} + +static inline uint32_t s_to_float32_int(uint64_t a) +{ + return ((a >> 32) & 0xc0000000) | ((a >> 29) & 0x3fffffff); +} + +static inline float32 s_to_float32(uint64_t a) +{ + CPU_FloatU r; + r.l = s_to_float32_int(a); + return r.f; +} + +uint32_t helper_s_to_memory(uint64_t a) +{ + return s_to_float32_int(a); +} + +uint64_t helper_memory_to_s(uint32_t a) +{ + return float32_to_s_int(a); +} + +uint64_t helper_adds(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float32 fa, fb, fr; + + fa = s_to_float32(a); + fb = s_to_float32(b); + fr = float32_add(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float32_to_s(fr); +} + +uint64_t helper_subs(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float32 fa, fb, fr; + + fa = s_to_float32(a); + fb = s_to_float32(b); + fr = float32_sub(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float32_to_s(fr); +} + +uint64_t helper_muls(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float32 fa, fb, fr; + + fa = s_to_float32(a); + fb = s_to_float32(b); + fr = float32_mul(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float32_to_s(fr); +} + +uint64_t helper_divs(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float32 fa, fb, fr; + + fa = s_to_float32(a); + fb = s_to_float32(b); + fr = float32_div(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float32_to_s(fr); +} + +uint64_t helper_sqrts(CPUAlphaState *env, uint64_t a) +{ + float32 fa, fr; + + fa = s_to_float32(a); + fr = float32_sqrt(fa, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float32_to_s(fr); +} + + +/* T floating (double) */ +static inline float64 t_to_float64(uint64_t a) +{ + /* Memory format is the same as float64 */ + CPU_DoubleU r; + r.ll = a; + return r.d; +} + +static inline uint64_t float64_to_t(float64 fa) +{ + /* Memory format is the same as float64 */ + CPU_DoubleU r; + r.d = fa; + return r.ll; +} + +uint64_t helper_addt(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb, fr; + + fa = t_to_float64(a); + fb = t_to_float64(b); + fr = float64_add(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float64_to_t(fr); +} + +uint64_t helper_subt(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb, fr; + + fa = t_to_float64(a); + fb = t_to_float64(b); + fr = float64_sub(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float64_to_t(fr); +} + +uint64_t helper_mult(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb, fr; + + fa = t_to_float64(a); + fb = t_to_float64(b); + fr = float64_mul(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float64_to_t(fr); +} + +uint64_t helper_divt(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb, fr; + + fa = t_to_float64(a); + fb = t_to_float64(b); + fr = float64_div(fa, fb, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float64_to_t(fr); +} + +uint64_t helper_sqrtt(CPUAlphaState *env, uint64_t a) +{ + float64 fa, fr; + + fa = t_to_float64(a); + fr = float64_sqrt(fa, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float64_to_t(fr); +} + +/* Comparisons */ +uint64_t helper_cmptun(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb; + uint64_t ret = 0; + + fa = t_to_float64(a); + fb = t_to_float64(b); + + if (float64_unordered_quiet(fa, fb, &FP_STATUS)) { + ret = 0x4000000000000000ULL; + } + env->error_code = soft_to_fpcr_exc(env); + + return ret; +} + +uint64_t helper_cmpteq(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb; + uint64_t ret = 0; + + fa = t_to_float64(a); + fb = t_to_float64(b); + + if (float64_eq_quiet(fa, fb, &FP_STATUS)) { + ret = 0x4000000000000000ULL; + } + env->error_code = soft_to_fpcr_exc(env); + + return ret; +} + +uint64_t helper_cmptle(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb; + uint64_t ret = 0; + + fa = t_to_float64(a); + fb = t_to_float64(b); + + if (float64_le(fa, fb, &FP_STATUS)) { + ret = 0x4000000000000000ULL; + } + env->error_code = soft_to_fpcr_exc(env); + + return ret; +} + +uint64_t helper_cmptlt(CPUAlphaState *env, uint64_t a, uint64_t b) +{ + float64 fa, fb; + uint64_t ret = 0; + + fa = t_to_float64(a); + fb = t_to_float64(b); + + if (float64_lt(fa, fb, &FP_STATUS)) { + ret = 0x4000000000000000ULL; + } + env->error_code = soft_to_fpcr_exc(env); + + return ret; +} + +/* Floating point format conversion */ +uint64_t helper_cvtts(CPUAlphaState *env, uint64_t a) +{ + float64 fa; + float32 fr; + + fa = t_to_float64(a); + fr = float64_to_float32(fa, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float32_to_s(fr); +} + +uint64_t helper_cvtst(CPUAlphaState *env, uint64_t a) +{ + float32 fa; + float64 fr; + + fa = s_to_float32(a); + fr = float32_to_float64(fa, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float64_to_t(fr); +} + +uint64_t helper_cvtqs(CPUAlphaState *env, uint64_t a) +{ + float32 fr = int64_to_float32(a, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + + return float32_to_s(fr); +} + +/* Implement float64 to uint64_t conversion without saturation -- we must + supply the truncated result. This behaviour is used by the compiler + to get unsigned conversion for free with the same instruction. */ + +static uint64_t do_cvttq(CPUAlphaState *env, uint64_t a, int roundmode) +{ + uint64_t frac, ret = 0; + uint32_t exp, sign, exc = 0; + int shift; + + sign = (a >> 63); + exp = (uint32_t)(a >> 52) & 0x7ff; + frac = a & 0xfffffffffffffull; + + if (exp == 0) { + if (unlikely(frac != 0) && !env->fp_status.flush_inputs_to_zero) { + goto do_underflow; + } + } else if (exp == 0x7ff) { + exc = FPCR_INV; + } else { + /* Restore implicit bit. */ + frac |= 0x10000000000000ull; + + shift = exp - 1023 - 52; + if (shift >= 0) { + /* In this case the number is so large that we must shift + the fraction left. There is no rounding to do. */ + if (shift < 64) { + ret = frac << shift; + } + /* Check for overflow. Note the special case of -0x1p63. */ + if (shift >= 11 && a != 0xC3E0000000000000ull) { + exc = FPCR_IOV | FPCR_INE; + } + } else { + uint64_t round; + + /* In this case the number is smaller than the fraction as + represented by the 52 bit number. Here we must think + about rounding the result. Handle this by shifting the + fractional part of the number into the high bits of ROUND. + This will let us efficiently handle round-to-nearest. */ + shift = -shift; + if (shift < 63) { + ret = frac >> shift; + round = frac << (64 - shift); + } else { + /* The exponent is so small we shift out everything. + Leave a sticky bit for proper rounding below. */ + do_underflow: + round = 1; + } + + if (round) { + exc = FPCR_INE; + switch (roundmode) { + case float_round_nearest_even: + if (round == (1ull << 63)) { + /* Fraction is exactly 0.5; round to even. */ + ret += (ret & 1); + } else if (round > (1ull << 63)) { + ret += 1; + } + break; + case float_round_to_zero: + break; + case float_round_up: + ret += 1 - sign; + break; + case float_round_down: + ret += sign; + break; + } + } + } + if (sign) { + ret = -ret; + } + } + env->error_code = exc; + + return ret; +} + +uint64_t helper_cvttq(CPUAlphaState *env, uint64_t a) +{ + return do_cvttq(env, a, FP_STATUS.float_rounding_mode); +} + +uint64_t helper_cvttq_c(CPUAlphaState *env, uint64_t a) +{ + return do_cvttq(env, a, float_round_to_zero); +} + +uint64_t helper_cvtqt(CPUAlphaState *env, uint64_t a) +{ + float64 fr = int64_to_float64(a, &FP_STATUS); + env->error_code = soft_to_fpcr_exc(env); + return float64_to_t(fr); +} + +uint64_t helper_cvtql(CPUAlphaState *env, uint64_t val) +{ + uint32_t exc = 0; + if (val != (int32_t)val) { + exc = FPCR_IOV | FPCR_INE; + } + env->error_code = exc; + + return ((val & 0xc0000000) << 32) | ((val & 0x3fffffff) << 29); +} |