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Diffstat (limited to 'src/math/hypotl.c')
| -rw-r--r-- | src/math/hypotl.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/src/math/hypotl.c b/src/math/hypotl.c new file mode 100644 index 00000000..f4a64f74 --- /dev/null +++ b/src/math/hypotl.c @@ -0,0 +1,148 @@ +/* origin: FreeBSD /usr/src/lib/msun/src/e_hypotl.c */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunSoft, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ +/* long double version of hypot(). See comments in hypot.c. */ + +#include "libm.h" + +#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 +long double hypotl(long double x, long double y) +{ + return hypot(x, y); +} +#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 + +#define GET_LDBL_EXPSIGN(i, v) do { \ + union IEEEl2bits uv; \ + \ + uv.e = v; \ + i = uv.xbits.expsign; \ +} while (0) + +#define GET_LDBL_MAN(h, l, v) do { \ + union IEEEl2bits uv; \ + \ + uv.e = v; \ + h = uv.bits.manh; \ + l = uv.bits.manl; \ +} while (0) + +#define SET_LDBL_EXPSIGN(v, i) do { \ + union IEEEl2bits uv; \ + \ + uv.e = v; \ + uv.xbits.expsign = i; \ + v = uv.e; \ +} while (0) + +#undef GET_HIGH_WORD +#define GET_HIGH_WORD(i, v) GET_LDBL_EXPSIGN(i, v) +#undef SET_HIGH_WORD +#define SET_HIGH_WORD(v, i) SET_LDBL_EXPSIGN(v, i) + +#define DESW(exp) (exp) /* delta expsign word */ +#define ESW(exp) (MAX_EXP - 1 + (exp)) /* expsign word */ +#define MANT_DIG LDBL_MANT_DIG +#define MAX_EXP LDBL_MAX_EXP + +#if LDBL_MANL_SIZE > 32 +typedef uint64_t man_t; +#else +typedef uint32_t man_t; +#endif + +long double hypotl(long double x, long double y) +{ + long double a=x,b=y,t1,t2,y1,y2,w; + int32_t j,k,ha,hb; + + GET_HIGH_WORD(ha, x); + ha &= 0x7fff; + GET_HIGH_WORD(hb, y); + hb &= 0x7fff; + if (hb > ha) { + a = y; + b = x; + j=ha; ha=hb; hb=j; + } else { + a = x; + b = y; + } + a = fabsl(a); + b = fabsl(b); + if (ha - hb > DESW(MANT_DIG+7)) /* x/y > 2**(MANT_DIG+7) */ + return a+b; + k = 0; + if (ha > ESW(MAX_EXP/2-12)) { /* a>2**(MAX_EXP/2-12) */ + if (ha >= ESW(MAX_EXP)) { /* Inf or NaN */ + man_t manh, manl; + /* Use original arg order iff result is NaN; quieten sNaNs. */ + w = fabsl(x+0.0)-fabsl(y+0.0); + GET_LDBL_MAN(manh,manl,a); + if (manh == LDBL_NBIT && manl == 0) w = a; + GET_LDBL_MAN(manh,manl,b); + if (hb >= ESW(MAX_EXP) && manh == LDBL_NBIT && manl == 0) w = b; + return w; + } + /* scale a and b by 2**-(MAX_EXP/2+88) */ + ha -= DESW(MAX_EXP/2+88); hb -= DESW(MAX_EXP/2+88); + k += MAX_EXP/2+88; + SET_HIGH_WORD(a, ha); + SET_HIGH_WORD(b, hb); + } + if (hb < ESW(-(MAX_EXP/2-12))) { /* b < 2**-(MAX_EXP/2-12) */ + if (hb <= 0) { /* subnormal b or 0 */ + man_t manh, manl; + GET_LDBL_MAN(manh,manl,b); + if ((manh|manl) == 0) + return a; + t1 = 0; + SET_HIGH_WORD(t1, ESW(MAX_EXP-2)); /* t1 = 2^(MAX_EXP-2) */ + b *= t1; + a *= t1; + k -= MAX_EXP-2; + } else { /* scale a and b by 2^(MAX_EXP/2+88) */ + ha += DESW(MAX_EXP/2+88); + hb += DESW(MAX_EXP/2+88); + k -= MAX_EXP/2+88; + SET_HIGH_WORD(a, ha); + SET_HIGH_WORD(b, hb); + } + } + /* medium size a and b */ + w = a - b; + if (w > b) { + t1 = a; + union IEEEl2bits uv; + uv.e = t1; uv.bits.manl = 0; t1 = uv.e; + t2 = a-t1; + w = sqrtl(t1*t1-(b*(-b)-t2*(a+t1))); + } else { + a = a+a; + y1 = b; + union IEEEl2bits uv; + uv.e = y1; uv.bits.manl = 0; y1 = uv.e; + y2 = b - y1; + t1 = a; + uv.e = t1; uv.bits.manl = 0; t1 = uv.e; + t2 = a - t1; + w = sqrtl(t1*y1-(w*(-w)-(t1*y2+t2*b))); + } + if(k!=0) { + uint32_t high; + t1 = 1.0; + GET_HIGH_WORD(high, t1); + SET_HIGH_WORD(t1, high+DESW(k)); + return t1*w; + } + return w; +} +#endif |