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

MIPS R6 introduced the following instruction:
Floating Point Fused Multiply Subtract:
MSUBF.fmt To perform a fused multiply-subtract of FP values.

MSUBF.fmt: FPR[fd] = FPR[fd] - (FPR[fs] x FPR[ft])

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10957/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 67390ec..54964b3 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -1778,6 +1778,19 @@
 			break;
 		}
 
+		case fmsubf_op: {
+			union ieee754sp ft, fs, fd;
+
+			if (!cpu_has_mips_r6)
+				return SIGILL;
+
+			SPFROMREG(ft, MIPSInst_FT(ir));
+			SPFROMREG(fs, MIPSInst_FS(ir));
+			SPFROMREG(fd, MIPSInst_FD(ir));
+			rv.s = ieee754sp_msubf(fd, fs, ft);
+			break;
+		}
+
 		case fabs_op:
 			handler.u = ieee754sp_abs;
 			goto scopuop;
@@ -2011,6 +2024,19 @@
 			break;
 		}
 
+		case fmsubf_op: {
+			union ieee754dp ft, fs, fd;
+
+			if (!cpu_has_mips_r6)
+				return SIGILL;
+
+			DPFROMREG(ft, MIPSInst_FT(ir));
+			DPFROMREG(fs, MIPSInst_FS(ir));
+			DPFROMREG(fd, MIPSInst_FD(ir));
+			rv.d = ieee754dp_msubf(fd, fs, ft);
+			break;
+		}
+
 		case fabs_op:
 			handler.u = ieee754dp_abs;
 			goto dcopuop;