softfloat library integration

This commit is contained in:
Blaise Tine
2021-10-10 13:20:50 -07:00
parent 28e26f3130
commit b8682f56ac
21 changed files with 400 additions and 818 deletions

View File

@@ -6,9 +6,9 @@
#include <climits>
#include <sys/types.h>
#include <sys/stat.h>
#include <cfenv>
#include <assert.h>
#include <util.h>
#include <rvfloats.h>
#include "warp.h"
#include "instr.h"
#include "core.h"
@@ -38,30 +38,14 @@ static bool HasDivergentThreads(const ThreadMask &thread_mask,
return false;
}
static void update_fcrs(Core* core, int tid, int wid, bool outOfRange = false) {
if (fetestexcept(FE_INEXACT)) {
core->set_csr(CSR_FCSR, core->get_csr(CSR_FCSR, tid, wid) | 0x1, tid, wid); // set NX bit
core->set_csr(CSR_FFLAGS, core->get_csr(CSR_FFLAGS, tid, wid) | 0x1, tid, wid); // set NX bit
}
if (fetestexcept(FE_UNDERFLOW)) {
core->set_csr(CSR_FCSR, core->get_csr(CSR_FCSR, tid, wid) | 0x2, tid, wid); // set UF bit
core->set_csr(CSR_FFLAGS, core->get_csr(CSR_FFLAGS, tid, wid) | 0x2, tid, wid); // set UF bit
}
inline uint32_t get_fpu_rm(uint32_t func3, Core* core, uint32_t tid, uint32_t wid) {
return (func3 == 0x7) ? core->get_csr(CSR_FRM, tid, wid) : func3;
}
if (fetestexcept(FE_OVERFLOW)) {
core->set_csr(CSR_FCSR, core->get_csr(CSR_FCSR, tid, wid) | 0x4, tid, wid); // set OF bit
core->set_csr(CSR_FFLAGS, core->get_csr(CSR_FFLAGS, tid, wid) | 0x4, tid, wid); // set OF bit
}
if (fetestexcept(FE_DIVBYZERO)) {
core->set_csr(CSR_FCSR, core->get_csr(CSR_FCSR, tid, wid) | 0x8, tid, wid); // set DZ bit
core->set_csr(CSR_FFLAGS, core->get_csr(CSR_FFLAGS, tid, wid) | 0x8, tid, wid); // set DZ bit
}
if (fetestexcept(FE_INVALID) || outOfRange) {
core->set_csr(CSR_FCSR, core->get_csr(CSR_FCSR, tid, wid) | 0x10, tid, wid); // set NV bit
core->set_csr(CSR_FFLAGS, core->get_csr(CSR_FFLAGS, tid, wid) | 0x10, tid, wid); // set NV bit
inline void update_fcrs(uint32_t fflags, Core* core, uint32_t tid, uint32_t wid) {
if (fflags) {
core->set_csr(CSR_FCSR, core->get_csr(CSR_FCSR, tid, wid) | fflags, tid, wid);
core->set_csr(CSR_FFLAGS, core->get_csr(CSR_FFLAGS, tid, wid) | fflags, tid, wid);
}
}
@@ -514,320 +498,120 @@ void Warp::execute(const Instr &instr, Pipeline *pipeline) {
}
}
break;
case FCI: // floating point computational instruction
case FCI: {
uint32_t frm = get_fpu_rm(func3, core_, t, id_);
uint32_t fflags = 0;
switch (func7) {
case 0x00: //FADD
case 0x04: //FSUB
case 0x08: //FMUL
case 0x0c: //FDIV
case 0x2c: //FSQRT
{
if (fpBinIsNan(rsdata[0]) || fpBinIsNan(rsdata[1])) {
// if one of op is NaN, one of them is not quiet NaN, them set FCSR
if ((fpBinIsNan(rsdata[0])==2) | (fpBinIsNan(rsdata[1])==2)) {
core_->set_csr(CSR_FCSR, core_->get_csr(CSR_FCSR, t, id_) | 0x10, t, id_); // set NV bit
core_->set_csr(CSR_FFLAGS, core_->get_csr(CSR_FFLAGS, t, id_) | 0x10, t, id_); // set NV bit
}
if (fpBinIsNan(rsdata[0]) && fpBinIsNan(rsdata[1]))
rddata = 0x7fc00000; // canonical(quiet) NaN
else if (fpBinIsNan(rsdata[0]))
rddata = rsdata[1];
else
rddata = rsdata[0];
} else {
float fpsrc_0 = *(float*)&rsdata[0];
float fpsrc_1 = *(float*)&rsdata[1];
float fpDest;
feclearexcept(FE_ALL_EXCEPT);
if (func7 == 0x00) // FADD
fpDest = fpsrc_0 + fpsrc_1;
else if (func7==0x04) // FSUB
fpDest = fpsrc_0 - fpsrc_1;
else if (func7==0x08) // FMUL
fpDest = fpsrc_0 * fpsrc_1;
else if (func7==0x0c) // FDIV
fpDest = fpsrc_0 / fpsrc_1;
else if (func7==0x2c) // FSQRT
fpDest = sqrt(fpsrc_0);
else {
std::abort();
}
// update fcsrs
update_fcrs(core_, t, id_);
D(3, "fpDest: " << fpDest);
if (fpBinIsNan(floatToBin(fpDest)) == 0) {
rddata = floatToBin(fpDest);
} else {
// According to risc-v spec p.64 section 11.3
// If the result is NaN, it is the canonical NaN
rddata = 0x7fc00000;
}
}
} break;
// FSGNJ.S, FSGNJN.S, FSGNJX.S
case 0x10: {
bool fsign1 = rsdata[0] & 0x80000000;
uint32_t fdata1 = rsdata[0] & 0x7FFFFFFF;
bool fsign2 = rsdata[1] & 0x80000000;
switch (func3) {
case 0: // FSGNJ.S
rddata = (fsign2 << 31) | fdata1;
break;
case 1: // FSGNJN.S
fsign2 = !fsign2;
rddata = (fsign2 << 31) | fdata1;
break;
case 2: { // FSGNJX.S
bool sign = fsign1 ^ fsign2;
rddata = (sign << 31) | fdata1;
} break;
}
} break;
// FMIN.S, FMAX.S
case 0x14: {
if (fpBinIsNan(rsdata[0]) || fpBinIsNan(rsdata[1])) { // if one of src is NaN
// one of them is not quiet NaN, them set FCSR
if ((fpBinIsNan(rsdata[0])==2) | (fpBinIsNan(rsdata[1])==2)) {
core_->set_csr(CSR_FCSR, core_->get_csr(CSR_FCSR, t, id_) | 0x10, t, id_); // set NV bit
core_->set_csr(CSR_FFLAGS, core_->get_csr(CSR_FFLAGS, t, id_) | 0x10, t, id_); // set NV bit
}
if (fpBinIsNan(rsdata[0]) && fpBinIsNan(rsdata[1]))
rddata = 0x7fc00000; // canonical(quiet) NaN
else if (fpBinIsNan(rsdata[0]))
rddata = rsdata[1];
else
rddata = rsdata[0];
} else {
uint8_t sr0IsZero = fpBinIsZero(rsdata[0]);
uint8_t sr1IsZero = fpBinIsZero(rsdata[1]);
if (sr0IsZero && sr1IsZero && (sr0IsZero != sr1IsZero)) {
// both are zero and not equal
// handle corner case that compare +0 and -0
if (func3) {
// FMAX.S
rddata = (sr1IsZero==2) ? rsdata[1] : rsdata[0];
} else {
// FMIM.S
rddata = (sr1IsZero==2) ? rsdata[0] : rsdata[1];
}
} else {
float rs1 = *(float*)&rsdata[0];
float rs2 = *(float*)&rsdata[1];
if (func3) {
// FMAX.S
float fmax = std::max(rs1, rs2);
rddata = floatToBin(fmax);
} else {
// FMIN.S
float fmin = std::min(rs1, rs2);
rddata = floatToBin(fmin);
}
}
}
} break;
// FCVT.W.S FCVT.WU.S
case 0x60: {
float fpSrc = *(float*)&rsdata[0];
Word result;
bool outOfRange = false;
if (rsrc1 == 0) {
// FCVT.W.S
// Convert floating point to 32-bit signed integer
if (fpSrc > pow(2.0, 31) - 1 || fpBinIsNan(rsdata[0]) || fpBinIsInf(rsdata[0]) == 2) {
feclearexcept(FE_ALL_EXCEPT);
outOfRange = true;
// result = 2^31 - 1
result = 0x7FFFFFFF;
} else if (fpSrc < -1*pow(2.0, 31) || fpBinIsInf(rsdata[0]) == 1) {
feclearexcept(FE_ALL_EXCEPT);
outOfRange = true;
// result = -1*2^31
result = 0x80000000;
} else {
feclearexcept(FE_ALL_EXCEPT);
result = (int32_t) fpSrc;
}
} else {
// FCVT.WU.S
// Convert floating point to 32-bit unsigned integer
if (fpSrc > pow(2.0, 32) - 1 || fpBinIsNan(rsdata[0]) || fpBinIsInf(rsdata[0]) == 2) {
feclearexcept(FE_ALL_EXCEPT);
outOfRange = true;
// result = 2^32 - 1
result = 0xFFFFFFFF;
} else if (fpSrc <= -1.0 || fpBinIsInf(rsdata[0]) == 1) {
feclearexcept(FE_ALL_EXCEPT);
outOfRange = true;
// result = 0
result = 0x00000000;
} else {
feclearexcept(FE_ALL_EXCEPT);
result = (uint32_t) fpSrc;
}
}
// update fcsrs
update_fcrs(core_, t, id_, outOfRange);
rddata = result;
} break;
// FMV.X.W FCLASS.S
case 0x70: {
// FCLASS.S
if (func3) {
// Examine the value in fpReg rs1 and write to integer rd
// a 10-bit mask to indicate the class of the fp number
rddata = 0; // clear all bits
bool fsign = rsdata[0] & 0x80000000;
uint32_t expo = (rsdata[0]>>23) & 0x000000FF;
uint32_t fraction = rsdata[0] & 0x007FFFFF;
if ((expo==0) && (fraction==0)) {
rddata = fsign ? (1<<3) : (1<<4); // +/- 0
} else if ((expo==0) && (fraction!=0)) {
rddata = fsign ? (1<<2) : (1<<5); // +/- subnormal
} else if ((expo==0xFF) && (fraction==0)) {
rddata = fsign ? (1<<0) : (1<<7); // +/- infinity
} else if ((expo==0xFF) && (fraction!=0)) {
if (!fsign && (fraction == 0x00400000)) {
rddata = (1<<9); // quiet NaN
} else {
rddata = (1<<8); // signaling NaN
}
} else {
rddata = fsign ? (1<<1) : (1<<6); // +/- normal
}
} else {
// FMV.X.W
// Move bit values from floating-point register rs1 to integer register rd
// Since we are using integer register to represent floating point register,
// just simply assign here.
rddata = rsdata[0];
}
} break;
// FEQ.S FLT.S FLE.S
// rdest is integer register
case 0x50: {
// TODO: FLT.S and FLE.S perform IEEE 754-2009, signaling comparisons, set
// TODO: the invalid operation exception flag if either input is NaN
if (fpBinIsNan(rsdata[0]) || fpBinIsNan(rsdata[1])) {
// FLE.S or FLT.S
if (func3 == 0 || func3 == 1) {
// If either input is NaN, set NV bit
core_->set_csr(CSR_FCSR, core_->get_csr(CSR_FCSR, t, id_) | 0x10, t, id_); // set NV bit
core_->set_csr(CSR_FFLAGS, core_->get_csr(CSR_FFLAGS, t, id_) | 0x10, t, id_); // set NV bit
} else { // FEQ.S
// Only set NV bit if it is signaling NaN
if (fpBinIsNan(rsdata[0]) == 2 || fpBinIsNan(rsdata[1]) == 2) {
// If either input is NaN, set NV bit
core_->set_csr(CSR_FCSR, core_->get_csr(CSR_FCSR, t, id_) | 0x10, t, id_); // set NV bit
core_->set_csr(CSR_FFLAGS, core_->get_csr(CSR_FFLAGS, t, id_) | 0x10, t, id_); // set NV bit
}
}
// The result is 0 if either operand is NaN
rddata = 0;
} else {
switch(func3) {
case 0: {
// FLE.S
rddata = (*(float*)&rsdata[0] <= *(float*)&rsdata[1]);
} break;
case 1: {
// FLT.S
rddata = (*(float*)&rsdata[0] < *(float*)&rsdata[1]);
} break;
case 2: {
// FEQ.S
rddata = (*(float*)&rsdata[0] == *(float*)&rsdata[1]);
} break;
default:
std::abort();
}
}
} break;
case 0x68:
// Cast integer to floating point
if (rsrc1) {
// FCVT.S.WU: convert 32-bit unsigned integer to floating point
float data = rsdata[0];
rddata = floatToBin(data);
} else {
// FCVT.S.W: convert 32-bit signed integer to floating point
// rsdata[0] is actually a unsigned number
float data = (WordI)rsdata[0];
rddata = floatToBin(data);
}
case 0x00: //FADD
rddata = rv_fadd(rsdata[0], rsdata[1], frm, &fflags);
break;
case 0x78: {
// FMV.W.X
// Move bit values from integer register rs1 to floating register rd
// Since we are using integer register to represent floating point register,
// just simply assign here.
rddata = rsdata[0];
case 0x04: //FSUB
rddata = rv_fsub(rsdata[0], rsdata[1], frm, &fflags);
break;
case 0x08: //FMUL
rddata = rv_fmul(rsdata[0], rsdata[1], frm, &fflags);
break;
case 0x0c: //FDIV
rddata = rv_fdiv(rsdata[0], rsdata[1], frm, &fflags);
break;
case 0x2c: //FSQRT
rddata = rv_fsqrt(rsdata[0], frm, &fflags);
break;
case 0x10:
switch (func3) {
case 0: // FSGNJ.S
rddata = rv_fsgnj(rsdata[0], rsdata[1]);
break;
case 1: // FSGNJN.S
rddata = rv_fsgnjn(rsdata[0], rsdata[1]);
break;
case 2: // FSGNJX.S
rddata = rv_fsgnjx(rsdata[0], rsdata[1]);
break;
}
break;
case 0x14:
if (func3) {
// FMAX.S
rddata = rv_fmax(rsdata[0], rsdata[1], &fflags);
} else {
// FMIN.S
rddata = rv_fmin(rsdata[0], rsdata[1], &fflags);
}
break;
case 0x60:
if (rsrc1 == 0) {
// FCVT.W.S
rddata = rv_ftoi(rsdata[0], frm, &fflags);
} else {
// FCVT.WU.S
rddata = rv_ftou(rsdata[0], frm, &fflags);
}
break;
case 0x70:
if (func3) {
// FCLASS.S
rddata = rv_fclss(rsdata[0]);
} else {
// FMV.X.W
rddata = rsdata[0];
}
break;
case 0x50:
switch(func3) {
case 0:
// FLE.S
rddata = rv_fle(rsdata[0], rsdata[1], &fflags);
break;
case 1:
// FLT.S
rddata = rv_flt(rsdata[0], rsdata[1], &fflags);
break;
case 2:
// FEQ.S
rddata = rv_feq(rsdata[0], rsdata[1], &fflags);
break;
} break;
case 0x68:
if (rsrc1) {
// FCVT.S.WU:
rddata = rv_utof(rsdata[0], frm, &fflags);
} else {
// FCVT.S.W:
rddata = rv_itof(rsdata[0], frm, &fflags);
}
break;
case 0x78:
// FMV.W.X
rddata = rsdata[0];
break;
}
update_fcrs(fflags, core_, t, id_);
rd_write = true;
break;
} break;
case FMADD:
case FMSUB:
case FMNMADD:
case FMNMSUB: {
// multiplicands are infinity and zero, them set FCSR
if (fpBinIsZero(rsdata[0]) || fpBinIsZero(rsdata[1]) || fpBinIsInf(rsdata[0]) || fpBinIsInf(rsdata[1])) {
core_->set_csr(CSR_FCSR, core_->get_csr(CSR_FCSR, t, id_) | 0x10, t, id_); // set NV bit
core_->set_csr(CSR_FFLAGS, core_->get_csr(CSR_FFLAGS, t, id_) | 0x10, t, id_); // set NV bit
}
if (fpBinIsNan(rsdata[0]) || fpBinIsNan(rsdata[1]) || fpBinIsNan(rsdata[2])) {
// if one of op is NaN, if addend is not quiet NaN, them set FCSR
if ((fpBinIsNan(rsdata[0])==2) | (fpBinIsNan(rsdata[1])==2) | (fpBinIsNan(rsdata[1])==2)) {
core_->set_csr(CSR_FCSR, core_->get_csr(CSR_FCSR, t, id_) | 0x10, t, id_); // set NV bit
core_->set_csr(CSR_FFLAGS, core_->get_csr(CSR_FFLAGS, t, id_) | 0x10, t, id_); // set NV bit
}
rddata = 0x7fc00000; // canonical(quiet) NaN
} else {
float rs1 = *(float*)&rsdata[0];
float rs2 = *(float*)&rsdata[1];
float rs3 = *(float*)&rsdata[2];
float fpDest(0.0);
feclearexcept(FE_ALL_EXCEPT);
switch (opcode) {
case FMADD:
// rd = (rs1*rs2)+rs3
fpDest = (rs1 * rs2) + rs3; break;
case FMSUB:
// rd = (rs1*rs2)-rs3
fpDest = (rs1 * rs2) - rs3; break;
case FMNMADD:
// rd = -(rs1*rs2)+rs3
fpDest = -1*(rs1 * rs2) - rs3; break;
case FMNMSUB:
// rd = -(rs1*rs2)-rs3
fpDest = -1*(rs1 * rs2) + rs3; break;
default:
std::abort();
break;
}
// update fcsrs
update_fcrs(core_, t, id_);
rddata = floatToBin(fpDest);
}
int frm = get_fpu_rm(func3, core_, t, id_);
Word fflags = 0;
switch (opcode) {
case FMADD:
rddata = rv_fmadd(rsdata[0], rsdata[1], rsdata[2], frm, &fflags);
break;
case FMSUB:
rddata = rv_fmsub(rsdata[0], rsdata[1], rsdata[2], frm, &fflags);
break;
case FMNMADD:
rddata = rv_fnmadd(rsdata[0], rsdata[1], rsdata[2], frm, &fflags);
break;
case FMNMSUB:
rddata = rv_fnmsub(rsdata[0], rsdata[1], rsdata[2], frm, &fflags);
break;
default:
break;
}
update_fcrs(fflags, core_, t, id_);
rd_write = true;
} break;
case GPGPU: