ref: 9f76a7f6819ac04552b4fb6588156f3e4089d1d7
dir: /os/pc/fpi387.c/
/*
* Copyright © 1999 Vita Nuova Limited
*
* this doesn't attempt to implement 387 floating-point properties
* that aren't visible in the Inferno environment. in particular,
* all arithmetic is done in double precision, not extended precision.
* furthermore, the FP trap status isn't updated.
*/
#ifdef TEST
#include <u.h>
#include <libc.h>
#include <ureg.h>
#include "fpi.h"
#include "tst.h"
#else
#include <u.h>
#include "ureg.h"
#include "fpi.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#endif
#define fabs Fabs
typedef struct FPI FPI;
struct FPI {
char* name;
void (*f)(Ureg*, int, void*, Internal*, Internal*);
int dstf;
};
enum {
RndNearest = 0,
RndDown,
RndUp,
Rnd0,
C0 = 1<<8,
C1 = 1<<9,
C2 = 1<<10,
C3 = 1<<14,
};
int fpemudebug = 0;
static Internal fpconst[7] = { /* indexed by op&7 */
/* s, e, l, h */
{0, 0x3FF, 0x00000000, 0x08000000}, /* 1 */
{0, 0x400, 0x0BCD1B8A, 0x0D49A784}, /* l2t */
{0, 0x3FF, 0x095C17F0, 0x0B8AA3B2}, /* l2e */
{0, 0x400, 0x022168C2, 0x0C90FDAA}, /* pi */
{0, 0x3FD, 0x04FBCFF7, 0x09A209A8}, /* lg2 */
{0, 0x3FE, 0x07D1CF79, 0x0B17217F}, /* ln2 */
{0, 0x1, 0x00000000, 0x00000000}, /* z */
};
static Internal *fpstk(int i);
#define ST(x) (*fpstk((x)))
#define I387 (up->env->fpu)
/* BUG: check fetch (not worthwhile in Inferno) */
#define getubyte(a) (*(uchar*)(a))
#define getuword(a) (*(ushort*)(a))
#define getulong(a) (*(ulong*)(a))
static void
popfp(void)
{
ushort *s;
s = &I387.status;
*s = (*s & ~0x3800) | ((*s + 0x0800) & 0x3800);
}
static void
pushfp(void)
{
ushort *s;
s = &I387.status;
*s = (*s & ~0x3800) | ((*s + 0x3800) & 0x3800);
}
static Internal *
fpstk(int i)
{
return (Internal*)I387.istack[(i+(I387.status>>11))&7];
}
static void
fldc(Ureg*, int op, void*, Internal*, Internal *d)
{
*d = fpconst[op&7];
}
static void
fabs(Ureg*, int, void*, Internal*, Internal *d)
{
d->s = 0;
}
static void
fchs(Ureg*, int, void*, Internal*, Internal *d)
{
d->s ^= 1;
}
static void
fadd(Ureg*, int, void*, Internal *s, Internal *d)
{
Internal l, r;
l = *s;
r = *d;
(l.s == r.s? fpiadd: fpisub)(&l, &r, d);
}
static void
fsub(Ureg*, int, void*, Internal *s, Internal *d)
{
Internal l, r;
l = *s;
r = *d;
l.s ^= 1;
(l.s == r.s? fpiadd: fpisub)(&l, &r, d);
}
static void
fsubr(Ureg*, int, void*, Internal *s, Internal *d)
{
Internal l, r;
l = *s;
r = *d;
r.s ^= 1;
(l.s == r.s? fpiadd: fpisub)(&r, &l, d);
}
static void
fmul(Ureg*, int, void*, Internal *s, Internal *d)
{
Internal l, r;
l = *s;
r = *d;
fpimul(&l, &r, d);
}
static void
fdiv(Ureg*, int, void*, Internal *s, Internal *d)
{
Internal l, r;
l = *s;
r = *d;
fpidiv(&l, &r, d);
}
static void
fdivr(Ureg*, int, void*, Internal *s, Internal *d)
{
Internal l, r;
l = *s;
r = *d;
fpidiv(&r, &l, d);
}
static void
fcom(Ureg*, int, void*, Internal *s, Internal *d)
{
int i;
ushort *p;
p = &I387.status;
if(IsWeird(s) || IsWeird(d)){
*p |= C0|C2|C3;
/* BUG: should trap if not masked */
return;
}
*p &= ~(C0|C2|C3);
i = fpicmp(d, s);
if(i < 0)
*p |= C0;
else if(i == 0)
*p |= C3;
}
static void
fpush(Ureg*, int op, void*, Internal*, Internal*)
{
Internal *p;
p = &ST(op & 7);
pushfp();
ST(0) = *p;
}
static void
fmov(Ureg*, int, void*, Internal *s, Internal *d)
{
*d = *s;
}
static void
fmovr(Ureg*, int, void*, Internal *s, Internal *d)
{
*s = *d;
}
static void
fxch(Ureg*, int, void*, Internal *s, Internal *d)
{
Internal t;
t = *s; *s = *d; *d = t;
}
static void
frstor(Ureg*, int, void *s, Internal*, Internal*)
{
validaddr(s, 108, 0);
memmove(&I387, s, 108);
}
static void
fsave(Ureg*, int, void *d, Internal*, Internal*)
{
validaddr(d, 108, 1);
memmove(d, &I387, 108);
I387.control = 0x037F;
I387.status = 0;
I387.tag = 0;
}
static void
fstsw(Ureg*, int, void *d, Internal*, Internal*)
{
validaddr(d, 2, 1);
*(short*)d = I387.status;
}
static void
fldenv(Ureg*, int, void *s, Internal*, Internal*)
{
validaddr(s, 28, 0);
memmove(&I387, s, 28);
}
static void
fldcw(Ureg*, int, void *s, Internal*, Internal*)
{
validaddr(s, 2, 0);
I387.control = *(short*)s;
}
static void
fstenv(Ureg*, int, void *d, Internal*, Internal*)
{
validaddr(d, 4*7, 1);
memmove(d, &I387, 4*7);
}
static void
fstcw(Ureg*, int, void *d, Internal*, Internal*)
{
validaddr(d, 2, 1);
*(short*)d = I387.control;
}
static void
fincstp(Ureg*, int, void*, Internal*, Internal*)
{
popfp();
}
static void
fdecstp(Ureg*, int, void*, Internal*, Internal*)
{
pushfp();
}
static void
fscale(Ureg*, int, void*, Internal *s, Internal *d)
{
Word w;
fpii2w(&w, s); /* should truncate towards zero ... */
d->e += w;
}
static void
fstswax(Ureg *ur, int, void*, Internal*, Internal*)
{
ur->ax = (ur->ax & ~0xFFFF) | (I387.status & 0xFFFF);
}
static void
ftst(Ureg*, int, void*, Internal*, Internal *d)
{
ushort *p;
p = &I387.status;
if(IsWeird(d)){
*p |= C0|C2|C3;
return;
}
*p &= ~(C0|C2|C3);
fpinormalise(d);
if(IsZero(d))
*p |= C3;
else if(d->s)
*p |=C0;
}
static void
frndint(Ureg*, int, void*, Internal*, Internal *d)
{
fpiround(d); /* BUG: doesn't look at rounding mode */
}
static void
fnop(Ureg*, int, void*, Internal*, Internal*)
{
}
enum {
Fpop1= 1<<0,
Fpop2 = 1<<1,
Fload = 1<<2,
};
/*
* %e - effective address - Mod R/M value
* %f - floating point register F0-F7 - from Mod R/M register
*/
static void fload(Ureg*, int, void*, Internal*, Internal*);
static void fstore(Ureg*, int, void*, Internal*, Internal*);
#define X(a,b) (((a)<<2)|(b))
static FPI optab1[4][4] = { /* normal mod r/m operand */
[0] {
[0] {"FLDENV %e", fldenv, 0},
[1] {"FLDCW %e", fldcw, 0},
[2] {"FSTENV %e", fstenv, 0},
[3] {"FSTCW %e", fstcw, 0},
},
[1] {
[1] {"FMOVX %e,F0", nil, Fload},
[3] {"FMOVXP F0,%e", nil, Fpop1},
},
[2] {
[0] {"FRSTOR %e", frstor, 0},
[2] {"FSAVE %e", fsave, 0},
[3] {"FSTSW %e", fstsw, 0},
},
[3] {
[0] {"FMOVB %e", nil, 0},
[1] {"FMOVV %e,F0", nil, Fload},
[2] {"FMOVBP %e", nil, Fpop1},
[3] {"FMOVVP F0,%e", nil, Fpop1},
},
};
#undef X
static FPI optab2a[1<<3] = { /* A=0 */
[0] {"FADDx %e,F0", fadd, 0},
[1] {"FMULx %e,F0", fmul, 0},
[2] {"FCOMx %e,F0", fcom, 0},
[3] {"FCOMxP %e,F0", fcom, Fpop1},
[4] {"FSUBx %e,F0", fsub, 0},
[5] {"FSUBRx %e,F0", fsubr, 0}, /* ?? */
[6] {"FDIVx %e,F0", fdiv, 0},
[7] {"FDIVRx %e,F0", fdivr, 0}, /* ?? */
};
static FPI optab2b[1<<2] = { /* A=1, B=0,2,3 */
[0] {"FMOVx %e,F0", fload, Fload},
[2] {"FMOVx F0,%e", fstore, 0},
[3] {"FMOVxP F0,%e", fstore, Fpop1},
};
#define X(d,P,B) ((d<<4)|(P<<3)|B)
static FPI optab3a[1<<5] = { /* A=0 */
[X(0,0,0)] {"FADDD %f,F0", fadd, 0},
[X(1,0,0)] {"FADDD F0,%f", fadd, 0},
[X(1,1,0)] {"FADDDP F0,%f", fadd, Fpop1},
[X(0,0,1)] {"FMULD %f,F0", fmul, 0},
[X(1,0,1)] {"FMULD F0,%f", fmul, 0},
[X(1,1,1)] {"FMULDP F0,%f", fmul, Fpop1},
[X(0,0,2)] {"FCOMD %f,F0", fcom, 0},
[X(0,0,3)] {"FCOMDP %f,F0", fcom, Fpop1},
[X(1,1,3)] {"FCOMDPP", fcom, Fpop1|Fpop2},
[X(0,0,4)] {"FSUBD %f,F0", fsub, 0},
[X(1,0,4)] {"FSUBRD F0,%f", fsubr, 0},
[X(1,1,4)] {"FSUBRDP F0,%f", fsubr, Fpop1},
[X(0,0,5)] {"FSUBRD %f,F0", fsubr, 0},
[X(1,0,5)] {"FSUBD F0,%f", fsub, 0},
[X(1,1,5)] {"FSUBDP F0,%f", fsub, Fpop1},
[X(0,1,5)] {"FUCOMPP", fcom, Fpop1|Fpop2},
[X(0,0,6)] {"FDIVD %f,F0", fdiv, 0},
[X(1,0,6)] {"FDIVRD F0,%f", fdivr, 0},
[X(1,1,6)] {"FDIVRDP F0,%f", fdivr, Fpop1},
[X(0,0,7)] {"FDIVRD %f,F0", fdivr, 0},
[X(1,0,7)] {"FDIVD F0,%f", fdiv, 0},
[X(1,1,7)] {"FDIVDP F0,%f", fdiv, Fpop1},
};
static FPI optab3b[1<<5] = { /* A=1 */
[X(0,0,0)] {"FMOVD %f,F0", fmov, Fload},
[X(0,0,1)] {"FXCHD %f,F0", fxch, 0},
[X(0,0,2)] {"FNOP", fnop, 0}, /* F0 only */
[X(1,0,0)] {"FFREED %f", fnop, 0},
[X(1,0,2)] {"FMOVD F0,%f", fmovr, 0},
[X(1,0,3)] {"FMOVDP F0,%f", fmovr, Fpop1},
[X(1,1,4)] {"FSTSW AX", fstswax, 0},
[X(1,0,4)] {"FUCOMD %f,F0", fcom, 0},
[X(1,0,5)] {"FUCOMDP %f,F0", fcom, Fpop1},
};
#undef X
static FPI optab4[1<<6] = {
[0x00] {"FCHS", fchs, 0},
[0x01] {"FABS", fabs, 0},
[0x04] {"FTST", ftst, 0},
[0x05] {"FXAM", nil, 0},
[0x08] {"FLD1", fldc, Fload},
[0x09] {"FLDL2T", fldc, Fload},
[0x0a] {"FLDL2E", fldc, Fload},
[0x0b] {"FLDPI", fldc, Fload},
[0x0c] {"FLDLG2", fldc, Fload},
[0x0d] {"FLDLN2", fldc, Fload},
[0x0e] {"FLDZ", fldc, Fload},
[0x10] {"F2XM1", nil, 0},
[0x11] {"FYL2X", nil, 0},
[0x12] {"FPTAN", nil, 0},
[0x13] {"FPATAN", nil, 0},
[0x14] {"FXTRACT", nil, 0},
[0x15] {"FPREM1", nil, 0},
[0x16] {"FDECSTP", fdecstp, 0},
[0x17] {"FINCSTP", fincstp, 0},
[0x18] {"FPREM", nil, 0},
[0x19] {"FYL2XP1", nil, 0},
[0x1a] {"FSQRT", nil, 0},
[0x1b] {"FSINCOS", nil, 0},
[0x1c] {"FRNDINT", frndint, 0},
[0x1d] {"FSCALE", fscale, 0},
[0x1e] {"FSIN", nil, 0},
[0x1f] {"FCOS", nil, 0},
};
static void
loadr32(void *s, Internal *d)
{
validaddr(s, 4, 0);
fpis2i(d, s);
}
static void
loadi32(void *s, Internal *d)
{
validaddr(s, 4, 0);
fpiw2i(d, s);
}
static void
loadr64(void *s, Internal *d)
{
validaddr(s, 8, 0);
fpid2i(d, s);
}
static void
loadi16(void *s, Internal *d)
{
Word w;
validaddr(s, 2, 0);
w = *(short*)s;
fpiw2i(d, &w);
}
static void (*loadf[4])(void*, Internal*) ={
loadr32, loadi32, loadr64, loadi16
};
static void
storer32(Internal s, void *d)
{
validaddr(d, 4, 1);
fpii2s(d, &s);
}
static void
storei32(Internal s, void *d)
{
validaddr(d, 4, 1);
fpii2w(d, &s);
}
static void
storer64(Internal s, void *d)
{
validaddr(d, 8, 1);
fpii2d(d, &s);
}
static void
storei16(Internal s, void *d)
{
Word w;
validaddr(d, 2, 1);
fpii2w(&w, &s);
if((short)w != w)
; /* overflow */
*(short*)d = w;
}
static void (*storef[4])(Internal, void*) ={
storer32, storei32, storer64, storei16
};
static void
fload(Ureg*, int op, void *mem, Internal*, Internal *d)
{
(*loadf[(op>>9)&3])(mem, d);
}
static void
fstore(Ureg*, int op, void *mem, Internal *s, Internal*)
{
(*storef[(op>>9)&3])(*s, mem);
}
#define REG(x) (*(ulong*)(((char*)ur)+roff[(x)]))
static int roff[] = {
offsetof(Ureg, ax),
offsetof(Ureg, cx),
offsetof(Ureg, dx),
offsetof(Ureg, bx),
offsetof(Ureg, ecode), /* ksp */
offsetof(Ureg, bp),
offsetof(Ureg, si),
offsetof(Ureg, di),
};
static long
getdisp(Ureg *ur, int mod, int rm)
{
uchar c;
long disp;
if(mod > 2)
return 0;
disp = 0;
if(mod == 1) {
c = getubyte(ur->pc++);
if(c&0x80)
disp = c|(~0<<8);
else
disp = c;
} else if(mod == 2 || rm == 5) {
disp = getulong(ur->pc);
ur->pc += 4;
}
if(mod || rm != 5)
disp += REG(rm); /* base */
return disp;
}
static ulong
modrm(Ureg *ur, uchar c)
{
uchar rm, mod;
int reg;
ulong base;
mod = (c>>6)&3;
rm = c&7;
if(mod == 3) /* register */
error("sys: fpemu: invalid addr mode");
/* no 16-bit mode */
if(rm == 4) { /* scummy sib byte */
c = getubyte(ur->pc++);
reg = (c>>3)&0x07; /* index */
base = getdisp(ur, mod, c&7);
if(reg != 4)
base += (REG(reg) << (c>>6)); /* index */
if(fpemudebug>1)
print("ur=#%lux sib=#%x reg=%d mod=%d base=%d basev=#%lux sp=%lux\n", ur, c, reg, mod, c&7, base, ur->usp);
return base;
}
if(rm == 5 && mod == 0){
ur->pc += 4;
return getulong(ur->pc-4);
}
return getdisp(ur, mod, rm);
}
static void *
ea(Ureg *ur, uchar op)
{
ulong addr;
addr = modrm(ur, op);
I387.operand = addr;
if(fpemudebug>1)
print("EA=#%lux\n", addr);
return (void*)addr;
}
void
fpi387(Ureg *ur)
{
int op, i;
ulong pc;
FPenv *ufp;
FPI *fp;
Internal tmp, *s, *d;
void *mem;
char buf[60];
ur->ecode = (ulong)&ur->sp; /* BUG: TEMPORARY compensation for incorrect Ureg for kernel mode */
ufp = &up->env->fpu; /* because all the state is in Osenv, it need not be saved/restored */
if(ufp->fpistate != FPACTIVE) {
ufp->fpistate = FPACTIVE;
ufp->control = 0x037f;
ufp->status = 0;
ufp->tag = 0;
ufp->oselector = 0x17;
}
while((op = getubyte(ur->pc)) >= 0xd8 && op <= 0xdf || op == 0x9B){
if(op == 0x9B){ /* WAIT */
ur->pc++;
continue;
}
if(ufp->control & ufp->status & 0x3F)
ufp->status |= 0x8000;
else
ufp->status &= 0x7FFF;
pc = ur->pc;
op = (op<<8) | getubyte(pc+1);
ufp->selector = ur->cs;
ufp->r4 = op-0xD800;
ur->pc += 2;
mem = nil;
s = nil;
d = nil;
/* decode op, following table 10.2.4 in i486 handbook */
i = op & 0xFFE0;
if(i == 0xD9E0){
fp = &optab4[op&0x1F];
s = &ST(0);
if(fp->dstf & Fload)
pushfp();
d = &ST(0);
} else if(i == 0xDBE0){
i = op & 0x1F;
if(i == 2){ /* FCLEX */
ufp->status &= 0x7f00;
continue;
} else if(i == 3){ /* FINIT */
ufp->control = 0x037f;
ufp->status = 0;
ufp->tag = 0;
continue;
}
fp = nil;
} else if((op & 0xF8C0) == 0xD8C0){
i = ((op>>6)&030)|((op>>3)&7);
if(op & (1<<8)){
fp = &optab3b[i];
s = &ST(op&7);
if(fp->dstf & Fload)
pushfp();
d = &ST(0);
} else {
fp = &optab3a[i];
i = op & 7;
if(op & (1<<10)){
s = &ST(0);
d = &ST(i);
}else{
s = &ST(i);
d = &ST(0);
}
}
} else if((op & 0xF920) == 0xD920){
mem = ea(ur, op&0xFF);
fp = &optab1[(op>>9)&3][(op>>3)&3];
} else {
mem = ea(ur, op&0xFF);
if(op & (1<<8)){
/* load/store */
fp = &optab2b[(op>>3)&7];
if(fp->dstf & Fload){
pushfp();
d = &ST(0);
} else
s = &ST(0);
} else {
/* mem OP reg */
fp = &optab2a[(op>>3)&7];
(*loadf[(op>>9)&3])(mem, &tmp);
s = &tmp;
d = &ST(0);
}
}
if(fp == nil || fp->f == nil){
if(fp == nil || fp->name == nil)
snprint(buf, sizeof(buf), "sys: fp: pc=%lux invalid fp 0x%.4x", pc, op);
else
snprint(buf, sizeof(buf), "sys: fp: pc=%lux unimp fp 0x%.4x (%s)", pc, op, fp->name);
error(buf);
}
if(fpemudebug)
print("%8.8lux %.4x %s\n", pc, op, fp->name);
(*fp->f)(ur, op, mem, s, d);
if(fp->dstf & Fpop1){
popfp();
if(fp->dstf & Fpop2)
popfp();
}
if(anyhigher())
sched();
}
}