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: 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>
diff --git a/arch/mips/math-emu/Makefile b/arch/mips/math-emu/Makefile
index 0037690..ea8db26 100644
--- a/arch/mips/math-emu/Makefile
+++ b/arch/mips/math-emu/Makefile
@@ -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 \
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index a348cbe..b65b4ea 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -1803,6 +1803,18 @@
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 @@
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;
diff --git a/arch/mips/math-emu/dp_2008class.c b/arch/mips/math-emu/dp_2008class.c
new file mode 100644
index 0000000..9dc39fc
--- /dev/null
+++ b/arch/mips/math-emu/dp_2008class.c
@@ -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;
+ }
+}
diff --git a/arch/mips/math-emu/ieee754.h b/arch/mips/math-emu/ieee754.h
index 8c78019..3b833ea 100644
--- a/arch/mips/math-emu/ieee754.h
+++ b/arch/mips/math-emu/ieee754.h
@@ -79,6 +79,7 @@
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 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
diff --git a/arch/mips/math-emu/sp_2008class.c b/arch/mips/math-emu/sp_2008class.c
new file mode 100644
index 0000000..ff62606
--- /dev/null
+++ b/arch/mips/math-emu/sp_2008class.c
@@ -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;
+ }
+}