[PATCH 04/11] MIPS: math-emu: Emulate MIPSr6 sel.fmt instruction

From: Paul Burton
Date: Thu Apr 21 2016 - 09:06:31 EST


Add support for emulating the MIPSr6 sel.fmt instruction, which was
previously missing from the FPU emulation code. This instruction selects
its result from 2 possible source registers, based upon bit 0 of the
destination register, and is valid only for S (single) & D (double) data
types.

Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---

arch/mips/math-emu/cp1emu.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 99977c3..85dd174 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -1675,7 +1675,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
union ieee754sp(*b) (union ieee754sp, union ieee754sp);
union ieee754sp(*u) (union ieee754sp);
} handler;
- union ieee754sp fs, ft;
+ union ieee754sp fd, fs, ft;

switch (MIPSInst_FUNC(ir)) {
/* binary ops */
@@ -1946,6 +1946,17 @@ copcsr:
rfmt = w_fmt;
goto copcsr;

+ case fsel_op:
+ if (!cpu_has_mips_r6)
+ return SIGILL;
+
+ SPFROMREG(fd, MIPSInst_FD(ir));
+ if (fd.bits & 0x1)
+ SPFROMREG(rv.s, MIPSInst_FT(ir));
+ else
+ SPFROMREG(rv.s, MIPSInst_FS(ir));
+ break;
+
case fcvtl_op:
if (!cpu_has_mips_3_4_5_64_r2_r6)
return SIGILL;
@@ -1994,7 +2005,7 @@ copcsr:
}

case d_fmt: {
- union ieee754dp fs, ft;
+ union ieee754dp fd, fs, ft;
union {
union ieee754dp(*b) (union ieee754dp, union ieee754dp);
union ieee754dp(*u) (union ieee754dp);
@@ -2244,6 +2255,17 @@ dcopuop:
rfmt = w_fmt;
goto copcsr;

+ case fsel_op:
+ if (!cpu_has_mips_r6)
+ return SIGILL;
+
+ DPFROMREG(fd, MIPSInst_FD(ir));
+ if (fd.bits & 0x1)
+ DPFROMREG(rv.d, MIPSInst_FT(ir));
+ else
+ DPFROMREG(rv.d, MIPSInst_FS(ir));
+ break;
+
case fcvtl_op:
if (!cpu_has_mips_3_4_5_64_r2_r6)
return SIGILL;
--
2.8.0