| // Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| #include "platform/globals.h" // NOLINT |
| |
| #if defined(TARGET_ARCH_ARM) |
| |
| #include "vm/constants.h" // NOLINT |
| |
| namespace dart { |
| |
| using dart::bit_cast; |
| |
| const char* const cpu_reg_names[kNumberOfCpuRegisters] = { |
| #if defined(DART_TARGET_OS_MACOS) || defined(DART_TARGET_OS_MACOS_IOS) |
| "r0", "r1", "r2", "r3", "r4", "pp", "r6", "fp", |
| "r8", "r9", "thr", "r11", "tmp", "sp", "lr", "pc", |
| #else |
| "r0", "r1", "r2", "r3", "r4", "pp", "r6", "r7", |
| "r8", "r9", "thr", "fp", "tmp", "sp", "lr", "pc", |
| #endif |
| }; |
| |
| const char* const cpu_reg_abi_names[kNumberOfCpuRegisters] = { |
| #if defined(DART_TARGET_OS_MACOS) || defined(DART_TARGET_OS_MACOS_IOS) |
| "r0", "r1", "r2", "r3", "r4", "r5", "r6", "fp", |
| "r8", "r9", "r10", "r11", "ip", "sp", "lr", "pc", |
| #else |
| "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", |
| "r8", "r9", "r10", "fp", "ip", "sp", "lr", "pc", |
| #endif |
| }; |
| |
| const char* const fpu_reg_names[kNumberOfFpuRegisters] = { |
| "q0", "q1", "q2", "q3", "q4", "q5", "q6", "q7", |
| #if defined(VFPv3_D32) |
| "q8", "q9", "q10", "q11", "q12", "q13", "q14", "q15", |
| #endif |
| }; |
| const char* const fpu_d_reg_names[kNumberOfDRegisters] = { |
| "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", |
| "d8", "d9", "d10", "d11", "d12", "d13", "d14", "d15", |
| #if defined(VFPv3_D32) |
| "d16", "d17", "d18", "d19", "d20", "d21", "d22", "d23", |
| "d24", "d25", "d26", "d27", "d28", "d29", "d30", "d31", |
| #endif |
| }; |
| const char* const fpu_s_reg_names[kNumberOfSRegisters] = { |
| "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7", "s8", "s9", "s10", |
| "s11", "s12", "s13", "s14", "s15", "s16", "s17", "s18", "s19", "s20", "s21", |
| "s22", "s23", "s24", "s25", "s26", "s27", "s28", "s29", "s30", "s31", |
| }; |
| |
| const Register CallingConventions::ArgumentRegisters[] = {R0, R1, R2, R3}; |
| |
| const FpuRegister CallingConventions::FpuArgumentRegisters[] = {Q0, Q1, Q2, Q3}; |
| const DRegister CallingConventions::FpuDArgumentRegisters[] = {D0, D1, D2, D3, |
| D4, D5, D6, D7}; |
| const SRegister CallingConventions::FpuSArgumentRegisters[] = { |
| S0, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15}; |
| |
| float ReciprocalEstimate(float a) { |
| // From the ARM Architecture Reference Manual A2-85. |
| if (isinf(a) || (fabs(a) >= exp2f(126))) |
| return a >= 0.0f ? 0.0f : -0.0f; |
| else if (a == 0.0f) |
| return 1.0f / a; |
| else if (isnan(a)) |
| return a; |
| |
| uint32_t a_bits = bit_cast<uint32_t, float>(a); |
| // scaled = '0011 1111 1110' : a<22:0> : Zeros(29) |
| uint64_t scaled = (static_cast<uint64_t>(0x3fe) << 52) | |
| ((static_cast<uint64_t>(a_bits) & 0x7fffff) << 29); |
| // result_exp = 253 - UInt(a<30:23>) |
| int32_t result_exp = 253 - ((a_bits >> 23) & 0xff); |
| ASSERT((result_exp >= 1) && (result_exp <= 252)); |
| |
| double scaled_d = bit_cast<double, uint64_t>(scaled); |
| ASSERT((scaled_d >= 0.5) && (scaled_d < 1.0)); |
| |
| // a in units of 1/512 rounded down. |
| int32_t q = static_cast<int32_t>(scaled_d * 512.0); |
| // reciprocal r. |
| double r = 1.0 / ((static_cast<double>(q) + 0.5) / 512.0); |
| // r in units of 1/256 rounded to nearest. |
| int32_t s = static_cast<int32_t>(256.0 * r + 0.5); |
| double estimate = static_cast<double>(s) / 256.0; |
| ASSERT((estimate >= 1.0) && (estimate <= (511.0 / 256.0))); |
| |
| // result = sign : result_exp<7:0> : estimate<51:29> |
| int32_t result_bits = |
| (a_bits & 0x80000000) | ((result_exp & 0xff) << 23) | |
| ((bit_cast<uint64_t, double>(estimate) >> 29) & 0x7fffff); |
| return bit_cast<float, int32_t>(result_bits); |
| } |
| |
| float ReciprocalStep(float op1, float op2) { |
| float p; |
| if ((isinf(op1) && op2 == 0.0f) || (op1 == 0.0f && isinf(op2))) { |
| p = 0.0f; |
| } else { |
| p = op1 * op2; |
| } |
| return 2.0f - p; |
| } |
| |
| float ReciprocalSqrtEstimate(float a) { |
| // From the ARM Architecture Reference Manual A2-87. |
| if (a < 0.0f) |
| return NAN; |
| else if (isinf(a) || (fabs(a) >= exp2f(126))) |
| return 0.0f; |
| else if (a == 0.0) |
| return 1.0f / a; |
| else if (isnan(a)) |
| return a; |
| |
| uint32_t a_bits = bit_cast<uint32_t, float>(a); |
| uint64_t scaled; |
| if (((a_bits >> 23) & 1) != 0) { |
| // scaled = '0 01111111101' : operand<22:0> : Zeros(29) |
| scaled = (static_cast<uint64_t>(0x3fd) << 52) | |
| ((static_cast<uint64_t>(a_bits) & 0x7fffff) << 29); |
| } else { |
| // scaled = '0 01111111110' : operand<22:0> : Zeros(29) |
| scaled = (static_cast<uint64_t>(0x3fe) << 52) | |
| ((static_cast<uint64_t>(a_bits) & 0x7fffff) << 29); |
| } |
| // result_exp = (380 - UInt(operand<30:23>) DIV 2; |
| int32_t result_exp = (380 - ((a_bits >> 23) & 0xff)) / 2; |
| |
| double scaled_d = bit_cast<double, uint64_t>(scaled); |
| ASSERT((scaled_d >= 0.25) && (scaled_d < 1.0)); |
| |
| double r; |
| if (scaled_d < 0.5) { |
| // range 0.25 <= a < 0.5 |
| |
| // a in units of 1/512 rounded down. |
| int32_t q0 = static_cast<int32_t>(scaled_d * 512.0); |
| // reciprocal root r. |
| r = 1.0 / sqrt((static_cast<double>(q0) + 0.5) / 512.0); |
| } else { |
| // range 0.5 <= a < 1.0 |
| |
| // a in units of 1/256 rounded down. |
| int32_t q1 = static_cast<int32_t>(scaled_d * 256.0); |
| // reciprocal root r. |
| r = 1.0 / sqrt((static_cast<double>(q1) + 0.5) / 256.0); |
| } |
| // r in units of 1/256 rounded to nearest. |
| int32_t s = static_cast<int>(256.0 * r + 0.5); |
| double estimate = static_cast<double>(s) / 256.0; |
| ASSERT((estimate >= 1.0) && (estimate <= (511.0 / 256.0))); |
| |
| // result = 0 : result_exp<7:0> : estimate<51:29> |
| int32_t result_bits = |
| ((result_exp & 0xff) << 23) | |
| ((bit_cast<uint64_t, double>(estimate) >> 29) & 0x7fffff); |
| return bit_cast<float, int32_t>(result_bits); |
| } |
| |
| float ReciprocalSqrtStep(float op1, float op2) { |
| float p; |
| if ((isinf(op1) && op2 == 0.0f) || (op1 == 0.0f && isinf(op2))) { |
| p = 0.0f; |
| } else { |
| p = op1 * op2; |
| } |
| return (3.0f - p) / 2.0f; |
| } |
| |
| } // namespace dart |
| |
| #endif // defined(TARGET_ARCH_ARM) |