From: Paul Burton Date: Thu, 21 Apr 2016 13:04:50 +0000 (+0100) Subject: MIPS: math-emu: Unify ieee754dp_m{add,sub}f X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d728f6709bcc49c98097485e3561f1faaf52b4f3;p=linux-beck.git MIPS: math-emu: Unify ieee754dp_m{add,sub}f The code for emulating MIPSr6 madd.d & msub.d instructions has previously been implemented as 2 different functions, namely ieee754dp_maddf & ieee754dp_msubf. The difference in behaviour of these 2 instructions is merely the sign of the product, so we can easily share the code implementing them. Do this for the double precision variant, removing the original ieee754dp_msubf in favor of reusing the code from ieee754dp_maddf. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13155/ Signed-off-by: Ralf Baechle --- diff --git a/arch/mips/math-emu/Makefile b/arch/mips/math-emu/Makefile index 3389aff21783..e9bbc2a6526f 100644 --- a/arch/mips/math-emu/Makefile +++ b/arch/mips/math-emu/Makefile @@ -4,7 +4,7 @@ obj-y += cp1emu.o ieee754dp.o ieee754sp.o ieee754.o \ dp_div.o dp_mul.o dp_sub.o dp_add.o dp_fsp.o dp_cmp.o dp_simple.o \ - dp_tint.o dp_fint.o dp_maddf.o dp_msubf.o dp_2008class.o dp_fmin.o dp_fmax.o \ + dp_tint.o dp_fint.o dp_maddf.o dp_2008class.o dp_fmin.o dp_fmax.o \ sp_div.o sp_mul.o sp_sub.o sp_add.o sp_fdp.o sp_cmp.o sp_simple.o \ sp_tint.o sp_fint.o sp_maddf.o sp_2008class.o sp_fmin.o sp_fmax.o \ dsemul.o diff --git a/arch/mips/math-emu/dp_maddf.c b/arch/mips/math-emu/dp_maddf.c index 119eda9fa1ea..d5e0fb13ef0f 100644 --- a/arch/mips/math-emu/dp_maddf.c +++ b/arch/mips/math-emu/dp_maddf.c @@ -14,8 +14,12 @@ #include "ieee754dp.h" -union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x, - union ieee754dp y) +enum maddf_flags { + maddf_negate_product = 1 << 0, +}; + +static union ieee754dp _dp_maddf(union ieee754dp z, union ieee754dp x, + union ieee754dp y, enum maddf_flags flags) { int re; int rs; @@ -154,6 +158,8 @@ union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x, re = xe + ye; rs = xs ^ ys; + if (flags & maddf_negate_product) + rs ^= 1; /* shunt to top of word */ xm <<= 64 - (DP_FBITS + 1); @@ -263,3 +269,15 @@ union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x, return ieee754dp_format(zs, ze, zm); } + +union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, 0); +} + +union ieee754dp ieee754dp_msubf(union ieee754dp z, union ieee754dp x, + union ieee754dp y) +{ + return _dp_maddf(z, x, y, maddf_negate_product); +} diff --git a/arch/mips/math-emu/dp_msubf.c b/arch/mips/math-emu/dp_msubf.c deleted file mode 100644 index 12241262f856..000000000000 --- a/arch/mips/math-emu/dp_msubf.c +++ /dev/null @@ -1,269 +0,0 @@ -/* - * IEEE754 floating point arithmetic - * double precision: MSUB.f (Fused Multiply Subtract) - * MSUBF.fmt: FPR[fd] = FPR[fd] - (FPR[fs] x FPR[ft]) - * - * MIPS floating point support - * Copyright (C) 2015 Imagination Technologies, Ltd. - * Author: Markos Chandras - * - * This program is free software; you can distribute it and/or modify it - * under the terms of the GNU General Public License as published by the - * Free Software Foundation; version 2 of the License. - */ - -#include "ieee754dp.h" - -union ieee754dp ieee754dp_msubf(union ieee754dp z, union ieee754dp x, - union ieee754dp y) -{ - int re; - int rs; - u64 rm; - unsigned lxm; - unsigned hxm; - unsigned lym; - unsigned hym; - u64 lrm; - u64 hrm; - u64 t; - u64 at; - int s; - - COMPXDP; - COMPYDP; - - u64 zm; int ze; int zs __maybe_unused; int zc; - - EXPLODEXDP; - EXPLODEYDP; - EXPLODEDP(z, zc, zs, ze, zm) - - FLUSHXDP; - FLUSHYDP; - FLUSHDP(z, zc, zs, ze, zm); - - ieee754_clearcx(); - - switch (zc) { - case IEEE754_CLASS_SNAN: - ieee754_setcx(IEEE754_INVALID_OPERATION); - return ieee754dp_nanxcpt(z); - case IEEE754_CLASS_DNORM: - DPDNORMx(zm, ze); - /* QNAN is handled separately below */ - } - - switch (CLPAIR(xc, yc)) { - case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): - case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): - case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): - case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): - case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): - return ieee754dp_nanxcpt(y); - - case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): - case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): - case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): - case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): - case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): - case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): - return ieee754dp_nanxcpt(x); - - case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): - case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): - case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): - case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): - return y; - - case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): - case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): - case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): - case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): - case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): - return x; - - - /* - * Infinity handling - */ - case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): - case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): - if (zc == IEEE754_CLASS_QNAN) - return z; - ieee754_setcx(IEEE754_INVALID_OPERATION); - return ieee754dp_indef(); - - case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): - case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): - case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): - case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): - case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): - if (zc == IEEE754_CLASS_QNAN) - return z; - return ieee754dp_inf(xs ^ ys); - - case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): - case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): - case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): - case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): - case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): - if (zc == IEEE754_CLASS_INF) - return ieee754dp_inf(zs); - /* Multiplication is 0 so just return z */ - return z; - - case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): - DPDNORMX; - - case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): - if (zc == IEEE754_CLASS_QNAN) - return z; - else if (zc == IEEE754_CLASS_INF) - return ieee754dp_inf(zs); - DPDNORMY; - break; - - case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): - if (zc == IEEE754_CLASS_QNAN) - return z; - else if (zc == IEEE754_CLASS_INF) - return ieee754dp_inf(zs); - DPDNORMX; - break; - - case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): - if (zc == IEEE754_CLASS_QNAN) - return z; - else if (zc == IEEE754_CLASS_INF) - return ieee754dp_inf(zs); - /* fall through to real computations */ - } - - /* Finally get to do some computation */ - - /* - * Do the multiplication bit first - * - * rm = xm * ym, re = xe + ye basically - * - * At this point xm and ym should have been normalized. - */ - assert(xm & DP_HIDDEN_BIT); - assert(ym & DP_HIDDEN_BIT); - - re = xe + ye; - rs = xs ^ ys; - - /* shunt to top of word */ - xm <<= 64 - (DP_FBITS + 1); - ym <<= 64 - (DP_FBITS + 1); - - /* - * Multiply 32 bits xm, ym to give high 32 bits rm with stickness. - */ - - /* 32 * 32 => 64 */ -#define DPXMULT(x, y) ((u64)(x) * (u64)y) - - lxm = xm; - hxm = xm >> 32; - lym = ym; - hym = ym >> 32; - - lrm = DPXMULT(lxm, lym); - hrm = DPXMULT(hxm, hym); - - t = DPXMULT(lxm, hym); - - at = lrm + (t << 32); - hrm += at < lrm; - lrm = at; - - hrm = hrm + (t >> 32); - - t = DPXMULT(hxm, lym); - - at = lrm + (t << 32); - hrm += at < lrm; - lrm = at; - - hrm = hrm + (t >> 32); - - rm = hrm | (lrm != 0); - - /* - * Sticky shift down to normal rounding precision. - */ - if ((s64) rm < 0) { - rm = (rm >> (64 - (DP_FBITS + 1 + 3))) | - ((rm << (DP_FBITS + 1 + 3)) != 0); - re++; - } else { - rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) | - ((rm << (DP_FBITS + 1 + 3 + 1)) != 0); - } - assert(rm & (DP_HIDDEN_BIT << 3)); - - /* And now the subtraction */ - - /* flip sign of r and handle as add */ - rs ^= 1; - - assert(zm & DP_HIDDEN_BIT); - - /* - * Provide guard,round and stick bit space. - */ - zm <<= 3; - - if (ze > re) { - /* - * Have to shift y fraction right to align. - */ - s = ze - re; - rm = XDPSRS(rm, s); - re += s; - } else if (re > ze) { - /* - * Have to shift x fraction right to align. - */ - s = re - ze; - zm = XDPSRS(zm, s); - ze += s; - } - assert(ze == re); - assert(ze <= DP_EMAX); - - if (zs == rs) { - /* - * Generate 28 bit result of adding two 27 bit numbers - * leaving result in xm, xs and xe. - */ - zm = zm + rm; - - if (zm >> (DP_FBITS + 1 + 3)) { /* carry out */ - zm = XDPSRS1(zm); - ze++; - } - } else { - if (zm >= rm) { - zm = zm - rm; - } else { - zm = rm - zm; - zs = rs; - } - if (zm == 0) - return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD); - - /* - * Normalize to rounding precision. - */ - while ((zm >> (DP_FBITS + 3)) == 0) { - zm <<= 1; - ze--; - } - } - - return ieee754dp_format(zs, ze, zm); -}