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-rw-r--r--arch/mips/math-emu/cp1emu.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 8f2f8e9d8b21..f2338d1c0b48 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -78,6 +78,9 @@ DEFINE_PER_CPU(struct mips_fpu_emulator_stats, fpuemustats);
#define FPCREG_RID 0 /* $0 = revision id */
#define FPCREG_CSR 31 /* $31 = csr */
+/* Determine rounding mode from the RM bits of the FCSR */
+#define modeindex(v) ((v) & FPU_CSR_RM)
+
/* Convert Mips rounding mode (0..3) to IEEE library modes. */
static const unsigned char ieee_rm[4] = {
[FPU_CSR_RN] = IEEE754_RN,
@@ -384,10 +387,14 @@ static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_struct *ctx)
(void *) (xcp->cp0_epc),
MIPSInst_RT(ir), value);
#endif
- value &= (FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
- ctx->fcr31 &= ~(FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
- /* convert to ieee library modes */
- ctx->fcr31 |= (value & ~0x3) | ieee_rm[value & 0x3];
+
+ /*
+ * Don't write reserved bits,
+ * and convert to ieee library modes
+ */
+ ctx->fcr31 = (value &
+ ~(FPU_CSR_RSVD | FPU_CSR_RM)) |
+ ieee_rm[modeindex(value)];
}
if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
return SIGFPE;

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