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MIPS: math-emu: Add support for the MIPS R6 CLASS FPU instruction

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MIPS R6 introduced the following instruction:
Stores in fd a bit mask reflecting the floating-point class of the
floating point scalar value fs.

CLASS.fmt: FPR[fd] = class(FPR[fs])

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10959/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Markos Chandras 2015-08-13 09:56:34 +02:00 committed by Ralf Baechle
parent 400bd2e413
commit 38db37ba06
5 changed files with 138 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
arch/mips/math-emu/Makefile
View file

@ -4,9 +4,9 @@
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_tint.o dp_fint.o dp_maddf.o dp_msubf.o dp_2008class.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_msubf.o \
sp_tint.o sp_fint.o sp_maddf.o sp_msubf.o sp_2008class.o \
dsemul.o
lib-y += ieee754d.o \

24
arch/mips/math-emu/cp1emu.c
View file

@ -1803,6 +1803,18 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
goto copcsr;
}
case fclass_op: {
union ieee754sp fs;
if (!cpu_has_mips_r6)
return SIGILL;
SPFROMREG(fs, MIPSInst_FS(ir));
rv.w = ieee754sp_2008class(fs);
rfmt = w_fmt;
break;
}
case fabs_op:
handler.u = ieee754sp_abs;
goto scopuop;
@ -2061,6 +2073,18 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
goto copcsr;
}
case fclass_op: {
union ieee754dp fs;
if (!cpu_has_mips_r6)
return SIGILL;
DPFROMREG(fs, MIPSInst_FS(ir));
rv.w = ieee754dp_2008class(fs);
rfmt = w_fmt;
break;
}
case fabs_op:
handler.u = ieee754dp_abs;
goto dcopuop;

55
arch/mips/math-emu/dp_2008class.c Normal file
View file

@ -0,0 +1,55 @@
/*
* IEEE754 floating point arithmetic
* double precision: CLASS.f
* FPR[fd] = class(FPR[fs])
*
* MIPS floating point support
* Copyright (C) 2015 Imagination Technologies, Ltd.
* Author: Markos Chandras <markos.chandras@imgtec.com>
*
* 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"
int ieee754dp_2008class(union ieee754dp x)
{
COMPXDP;
EXPLODEXDP;
/*
* 10 bit mask as follows:
*
* bit0 = SNAN
* bit1 = QNAN
* bit2 = -INF
* bit3 = -NORM
* bit4 = -DNORM
* bit5 = -ZERO
* bit6 = INF
* bit7 = NORM
* bit8 = DNORM
* bit9 = ZERO
*/
switch(xc) {
case IEEE754_CLASS_SNAN:
return 0x01;
case IEEE754_CLASS_QNAN:
return 0x02;
case IEEE754_CLASS_INF:
return 0x04 << (xs ? 0 : 4);
case IEEE754_CLASS_NORM:
return 0x08 << (xs ? 0 : 4);
case IEEE754_CLASS_DNORM:
return 0x10 << (xs ? 0 : 4);
case IEEE754_CLASS_ZERO:
return 0x20 << (xs ? 0 : 4);
default:
pr_err("Unknown class: %d\n", xc);
return 0;
}
}

2
arch/mips/math-emu/ieee754.h
View file

@ -79,6 +79,7 @@ union ieee754sp ieee754sp_maddf(union ieee754sp z, union ieee754sp x,
union ieee754sp y);
union ieee754sp ieee754sp_msubf(union ieee754sp z, union ieee754sp x,
union ieee754sp y);
int ieee754sp_2008class(union ieee754sp x);
/*
* double precision (often aka double)
@ -108,6 +109,7 @@ union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x,
union ieee754dp y);
union ieee754dp ieee754dp_msubf(union ieee754dp z, union ieee754dp x,
union ieee754dp y);
int ieee754dp_2008class(union ieee754dp x);
/* 5 types of floating point number

55
arch/mips/math-emu/sp_2008class.c Normal file
View file

@ -0,0 +1,55 @@
/*
* IEEE754 floating point arithmetic
* single precision: CLASS.f
* FPR[fd] = class(FPR[fs])
*
* MIPS floating point support
* Copyright (C) 2015 Imagination Technologies, Ltd.
* Author: Markos Chandras <markos.chandras@imgtec.com>
*
* 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 "ieee754sp.h"
int ieee754sp_2008class(union ieee754sp x)
{
COMPXSP;
EXPLODEXSP;
/*
* 10 bit mask as follows:
*
* bit0 = SNAN
* bit1 = QNAN
* bit2 = -INF
* bit3 = -NORM
* bit4 = -DNORM
* bit5 = -ZERO
* bit6 = INF
* bit7 = NORM
* bit8 = DNORM
* bit9 = ZERO
*/
switch(xc) {
case IEEE754_CLASS_SNAN:
return 0x01;
case IEEE754_CLASS_QNAN:
return 0x02;
case IEEE754_CLASS_INF:
return 0x04 << (xs ? 0 : 4);
case IEEE754_CLASS_NORM:
return 0x08 << (xs ? 0 : 4);
case IEEE754_CLASS_DNORM:
return 0x10 << (xs ? 0 : 4);
case IEEE754_CLASS_ZERO:
return 0x20 << (xs ? 0 : 4);
default:
pr_err("Unknown class: %d\n", xc);
return 0;
}
}