ref: bdd385803dcbccdf2750f7259a1784744541dec4
dir: /sys/src/libc/power/vlrt.c/
typedef unsigned long ulong;
typedef unsigned int uint;
typedef unsigned short ushort;
typedef unsigned char uchar;
typedef signed char schar;
#define SIGN(n) (1UL<<(n-1))
typedef struct Vlong Vlong;
struct Vlong
{
ulong hi;
ulong lo;
};
void abort(void);
void _divu64(Vlong, Vlong, Vlong*, Vlong*);
void
_d2v(Vlong *y, double d)
{
union { double d; Vlong; } x;
ulong xhi, xlo, ylo, yhi;
int sh;
x.d = d;
xhi = (x.hi & 0xfffff) | 0x100000;
xlo = x.lo;
sh = 1075 - ((x.hi >> 20) & 0x7ff);
ylo = 0;
yhi = 0;
if(sh >= 0) {
/* v = (hi||lo) >> sh */
if(sh < 32) {
if(sh == 0) {
ylo = xlo;
yhi = xhi;
} else {
ylo = (xlo >> sh) | (xhi << (32-sh));
yhi = xhi >> sh;
}
} else {
if(sh == 32) {
ylo = xhi;
} else
if(sh < 64) {
ylo = xhi >> (sh-32);
}
}
} else {
/* v = (hi||lo) << -sh */
sh = -sh;
if(sh <= 10) {
ylo = xlo << sh;
yhi = (xhi << sh) | (xlo >> (32-sh));
} else {
/* overflow */
yhi = d; /* causes something awful */
}
}
if(x.hi & SIGN(32)) {
if(ylo != 0) {
ylo = -ylo;
yhi = ~yhi;
} else
yhi = -yhi;
}
y->hi = yhi;
y->lo = ylo;
}
void
_f2v(Vlong *y, float f)
{
_d2v(y, f);
}
double
_v2d(Vlong x)
{
if(!x.lo) {
return (long)x.hi*4294967296.;
}
if(x.hi & SIGN(32)) {
x.lo = -x.lo;
x.hi = ~x.hi;
return -((long)x.hi*4294967296. + x.lo);
}
return (long)x.hi*4294967296. + x.lo;
}
float
_v2f(Vlong x)
{
return _v2d(x);
}
double
_uv2d(Vlong x)
{
return x.hi*4294967296. + x.lo;
}
float
_uv2f(Vlong x)
{
return _uv2d(x);
}
void
_vasaddd(Vlong *ret, Vlong *lv, double v2d(Vlong), double rv)
{
_d2v(lv, v2d(*lv)+rv);
*ret = *lv;
}
void
_vassubd(Vlong *ret, Vlong *lv, double v2d(Vlong), double rv)
{
_d2v(lv, v2d(*lv)-rv);
*ret = *lv;
}
void
_vasmuld(Vlong *ret, Vlong *lv, double v2d(Vlong), double rv)
{
_d2v(lv, v2d(*lv)*rv);
*ret = *lv;
}
void
_vasdivd(Vlong *ret, Vlong *lv, double v2d(Vlong), double rv)
{
_d2v(lv, v2d(*lv)/rv);
*ret = *lv;
}
void
_divvu(Vlong *q, Vlong n, Vlong d)
{
if(n.hi == 0 && d.hi == 0) {
q->hi = 0;
q->lo = n.lo / d.lo;
return;
}
_divu64(n, d, q, 0);
}
void
_modvu(Vlong *r, Vlong n, Vlong d)
{
if(n.hi == 0 && d.hi == 0) {
r->hi = 0;
r->lo = n.lo % d.lo;
return;
}
_divu64(n, d, 0, r);
}
static void
vneg(Vlong *v)
{
if(v->lo == 0) {
v->hi = -v->hi;
return;
}
v->lo = -v->lo;
v->hi = ~v->hi;
}
void
_divv(Vlong *q, Vlong n, Vlong d)
{
long nneg, dneg;
if(n.hi == (((long)n.lo)>>31) && d.hi == (((long)d.lo)>>31)) {
q->lo = (long)n.lo / (long)d.lo;
q->hi = ((long)q->lo) >> 31;
return;
}
nneg = n.hi >> 31;
if(nneg)
vneg(&n);
dneg = d.hi >> 31;
if(dneg)
vneg(&d);
_divu64(n, d, q, 0);
if(nneg != dneg)
vneg(q);
}
void
_modv(Vlong *r, Vlong n, Vlong d)
{
long nneg, dneg;
if(n.hi == (((long)n.lo)>>31) && d.hi == (((long)d.lo)>>31)) {
r->lo = (long)n.lo % (long)d.lo;
r->hi = ((long)r->lo) >> 31;
return;
}
nneg = n.hi >> 31;
if(nneg)
vneg(&n);
dneg = d.hi >> 31;
if(dneg)
vneg(&d);
_divu64(n, d, 0, r);
if(nneg)
vneg(r);
}
void
_vasop(Vlong *ret, void *lv, void fn(Vlong*, Vlong, Vlong), int type, Vlong rv)
{
Vlong t, u;
u = *ret;
switch(type) {
default:
abort();
break;
case 1: /* schar */
t.lo = *(schar*)lv;
t.hi = t.lo >> 31;
fn(&u, t, rv);
*(schar*)lv = u.lo;
break;
case 2: /* uchar */
t.lo = *(uchar*)lv;
t.hi = 0;
fn(&u, t, rv);
*(uchar*)lv = u.lo;
break;
case 3: /* short */
t.lo = *(short*)lv;
t.hi = t.lo >> 31;
fn(&u, t, rv);
*(short*)lv = u.lo;
break;
case 4: /* ushort */
t.lo = *(ushort*)lv;
t.hi = 0;
fn(&u, t, rv);
*(ushort*)lv = u.lo;
break;
case 9: /* int */
t.lo = *(int*)lv;
t.hi = t.lo >> 31;
fn(&u, t, rv);
*(int*)lv = u.lo;
break;
case 10: /* uint */
t.lo = *(uint*)lv;
t.hi = 0;
fn(&u, t, rv);
*(uint*)lv = u.lo;
break;
case 5: /* long */
t.lo = *(long*)lv;
t.hi = t.lo >> 31;
fn(&u, t, rv);
*(long*)lv = u.lo;
break;
case 6: /* ulong */
t.lo = *(ulong*)lv;
t.hi = 0;
fn(&u, t, rv);
*(ulong*)lv = u.lo;
break;
case 7: /* vlong */
case 8: /* uvlong */
fn(&u, *(Vlong*)lv, rv);
*(Vlong*)lv = u;
break;
}
*ret = u;
}