Commit 38db37ba authored by Markos Chandras's avatar Markos Chandras Committed by Ralf Baechle
Browse files

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



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: default avatarMarkos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10959/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 400bd2e4

arch/mips/math-emu/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -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 \

arch/mips/math-emu/cp1emu.c

+24 −0
Original line number Diff line number Diff line
@@ -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 @@ copcsr: 
			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;

arch/mips/math-emu/dp_2008class.c

0 → 100644
+55 −0
Original line number Diff line number Diff line 
/*

 * 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;

	}

}

arch/mips/math-emu/ieee754.h

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/mips/math-emu/sp_2008class.c

0 → 100644
+55 −0
Original line number Diff line number Diff line 
/*

 * 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;

	}

}

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