MIPS: math-emu: Switch to using the MIPS rounding modes.

Previously math-emu was using the IEEE-754 constants internally.  These
were differing by having the constants for rounding to +/- infinity
switched, so a conversion was necessary.  This would be entirely
avoidable if the MIPS constants were used throughout, so get rid of
the bloat.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/math-emu/cp1emu.c

@@ -67,21 +67,6 @@ static int fpux_emu(struct pt_regs *,
 /* 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,
-	[FPU_CSR_RZ] = IEEE754_RZ,
-	[FPU_CSR_RU] = IEEE754_RU,
-	[FPU_CSR_RD] = IEEE754_RD,
-};
-/* Convert IEEE library modes to MIPS rounding mode (0..3). */
-static const unsigned char mips_rm[4] = {
-	[IEEE754_RN] = FPU_CSR_RN,
-	[IEEE754_RZ] = FPU_CSR_RZ,
-	[IEEE754_RD] = FPU_CSR_RD,
-	[IEEE754_RU] = FPU_CSR_RU,
-};
-
 /* convert condition code register number to csr bit */
 static const unsigned int fpucondbit[8] = {
 	FPU_CSR_COND0,
@@ -907,8 +892,7 @@ emul:
 			/* cop control register rd -> gpr[rt] */
 			if (MIPSInst_RD(ir) == FPCREG_CSR) {
 				value = ctx->fcr31;
-				value = (value & ~FPU_CSR_RM) |
-					mips_rm[modeindex(value)];
+				value = (value & ~FPU_CSR_RM) | modeindex(value);
 				pr_debug("%p gpr[%d]<-csr=%08x\n",
 					 (void *) (xcp->cp0_epc),
 					 MIPSInst_RT(ir), value);
@@ -939,9 +923,8 @@ emul:
 				 * Don't write reserved bits,
 				 * and convert to ieee library modes
 				 */
-				ctx->fcr31 = (value &
-						~(FPU_CSR_RSVD | FPU_CSR_RM)) |
-						ieee_rm[modeindex(value)];
+				ctx->fcr31 = (value & ~(FPU_CSR_RSVD | FPU_CSR_RM)) |
+					     modeindex(value);
 			}
 			if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
 				return SIGFPE;
@@ -1515,7 +1498,7 @@ copcsr:
 
 			oldrm = ieee754_csr.rm;
 			SPFROMREG(fs, MIPSInst_FS(ir));
-			ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
+			ieee754_csr.rm = modeindex(MIPSInst_FUNC(ir));
 			rv.w = ieee754sp_tint(fs);
 			ieee754_csr.rm = oldrm;
 			rfmt = w_fmt;
@@ -1539,7 +1522,7 @@ copcsr:
 
 			oldrm = ieee754_csr.rm;
 			SPFROMREG(fs, MIPSInst_FS(ir));
-			ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
+			ieee754_csr.rm = modeindex(MIPSInst_FUNC(ir));
 			rv.l = ieee754sp_tlong(fs);
 			ieee754_csr.rm = oldrm;
 			rfmt = l_fmt;
@@ -1692,7 +1675,7 @@ dcopuop:
 
 			oldrm = ieee754_csr.rm;
 			DPFROMREG(fs, MIPSInst_FS(ir));
-			ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
+			ieee754_csr.rm = modeindex(MIPSInst_FUNC(ir));
 			rv.w = ieee754dp_tint(fs);
 			ieee754_csr.rm = oldrm;
 			rfmt = w_fmt;
@@ -1716,7 +1699,7 @@ dcopuop:
 
 			oldrm = ieee754_csr.rm;
 			DPFROMREG(fs, MIPSInst_FS(ir));
-			ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
+			ieee754_csr.rm = modeindex(MIPSInst_FUNC(ir));
 			rv.l = ieee754dp_tlong(fs);
 			ieee754_csr.rm = oldrm;
 			rfmt = l_fmt;
@@ -1926,11 +1909,7 @@ int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
 			 * ieee754_csr.	 But ieee754_csr.rm is ieee
 			 * library modes. (not mips rounding mode)
 			 */
-			/* convert to ieee library modes */
-			ieee754_csr.rm = ieee_rm[ieee754_csr.rm];
 			sig = cop1Emulate(xcp, ctx, dec_insn, fault_addr);
-			/* revert to mips rounding mode */
-			ieee754_csr.rm = mips_rm[ieee754_csr.rm];
 		}
 
 		if (has_fpu)

arch/mips/math-emu/dp_add.c

@@ -91,7 +91,7 @@ union ieee754dp ieee754dp_add(union ieee754dp x, union ieee754dp y)
 		if (xs == ys)
 			return x;
 		else
-			return ieee754dp_zero(ieee754_csr.rm == IEEE754_RD);
+			return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD);
 
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
@@ -168,7 +168,7 @@ union ieee754dp ieee754dp_add(union ieee754dp x, union ieee754dp y)
 			xs = ys;
 		}
 		if (xm == 0)
-			return ieee754dp_zero(ieee754_csr.rm == IEEE754_RD);
+			return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD);
 
 		/*
 		 * Normalize to rounding precision.

arch/mips/math-emu/dp_sqrt.c

@@ -80,7 +80,7 @@ union ieee754dp ieee754dp_sqrt(union ieee754dp x)
 	oldcsr = ieee754_csr;
 	ieee754_csr.mx &= ~IEEE754_INEXACT;
 	ieee754_csr.sx &= ~IEEE754_INEXACT;
-	ieee754_csr.rm = IEEE754_RN;
+	ieee754_csr.rm = FPU_CSR_RN;
 
 	/* adjust exponent to prevent overflow */
 	scalx = 0;
@@ -122,7 +122,7 @@ union ieee754dp ieee754dp_sqrt(union ieee754dp x)
 	/* twiddle last bit to force y correctly rounded */
 
 	/* set RZ, clear INEX flag */
-	ieee754_csr.rm = IEEE754_RZ;
+	ieee754_csr.rm = FPU_CSR_RZ;
 	ieee754_csr.sx &= ~IEEE754_INEXACT;
 
 	/* t=x/y; ...chopped quotient, possibly inexact */
@@ -139,10 +139,10 @@ union ieee754dp ieee754dp_sqrt(union ieee754dp x)
 		oldcsr.sx |= IEEE754_INEXACT;
 
 		switch (oldcsr.rm) {
-		case IEEE754_RU:
+		case FPU_CSR_RU:
 			y.bits += 1;
 			/* drop through */
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			t.bits += 1;
 			break;
 		}

arch/mips/math-emu/dp_sub.c

@@ -91,7 +91,7 @@ union ieee754dp ieee754dp_sub(union ieee754dp x, union ieee754dp y)
 		if (xs != ys)
 			return x;
 		else
-			return ieee754dp_zero(ieee754_csr.rm == IEEE754_RD);
+			return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD);
 
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
@@ -171,7 +171,7 @@ union ieee754dp ieee754dp_sub(union ieee754dp x, union ieee754dp y)
 			xs = ys;
 		}
 		if (xm == 0) {
-			if (ieee754_csr.rm == IEEE754_RD)
+			if (ieee754_csr.rm == FPU_CSR_RD)
 				return ieee754dp_zero(1);	/* round negative inf. => sign = -1 */
 			else
 				return ieee754dp_zero(0);	/* other round modes   => sign = 1 */

arch/mips/math-emu/dp_tint.c

@@ -74,17 +74,17 @@ int ieee754dp_tint(union ieee754dp x)
 		   to be zero */
 		odd = (xm & 0x1) != 0x0;
 		switch (ieee754_csr.rm) {
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			if (round && (sticky || odd))
 				xm++;
 			break;
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			break;
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if ((round || sticky) && !xs)
 				xm++;
 			break;
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if ((round || sticky) && xs)
 				xm++;
 			break;

arch/mips/math-emu/dp_tlong.c

@@ -79,17 +79,17 @@ s64 ieee754dp_tlong(union ieee754dp x)
 		}
 		odd = (xm & 0x1) != 0x0;
 		switch (ieee754_csr.rm) {
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			if (round && (sticky || odd))
 				xm++;
 			break;
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			break;
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if ((round || sticky) && !xs)
 				xm++;
 			break;
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if ((round || sticky) && xs)
 				xm++;
 			break;

arch/mips/math-emu/ieee754.h

@@ -126,13 +126,6 @@ enum {
 #define IEEE754_CGT	0x04
 #define IEEE754_CUN	0x08
 
-/* rounding mode
-*/
-#define IEEE754_RN	0	/* round to nearest */
-#define IEEE754_RZ	1	/* round toward zero  */
-#define IEEE754_RD	2	/* round toward -Infinity */
-#define IEEE754_RU	3	/* round toward +Infinity */
-
 /* "normal" comparisons
 */
 static inline int ieee754sp_eq(union ieee754sp x, union ieee754sp y)

arch/mips/math-emu/ieee754dp.c

@@ -67,17 +67,17 @@ static u64 ieee754dp_get_rounding(int sn, u64 xm)
 	 */
 	if (xm & (DP_MBIT(3) - 1)) {
 		switch (ieee754_csr.rm) {
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			break;
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			xm += 0x3 + ((xm >> 3) & 1);
 			/* xm += (xm&0x8)?0x4:0x3 */
 			break;
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if (!sn)	/* ?? */
 				xm += 0x8;
 			break;
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if (sn) /* ?? */
 				xm += 0x8;
 			break;
@@ -108,15 +108,15 @@ union ieee754dp ieee754dp_format(int sn, int xe, u64 xm)
 			ieee754_setcx(IEEE754_INEXACT);
 
 			switch(ieee754_csr.rm) {
-			case IEEE754_RN:
-			case IEEE754_RZ:
+			case FPU_CSR_RN:
+			case FPU_CSR_RZ:
 				return ieee754dp_zero(sn);
-			case IEEE754_RU:    /* toward +Infinity */
+			case FPU_CSR_RU:    /* toward +Infinity */
 				if (sn == 0)
 					return ieee754dp_min(0);
 				else
 					return ieee754dp_zero(1);
-			case IEEE754_RD:    /* toward -Infinity */
+			case FPU_CSR_RD:    /* toward -Infinity */
 				if (sn == 0)
 					return ieee754dp_zero(0);
 				else
@@ -172,16 +172,16 @@ union ieee754dp ieee754dp_format(int sn, int xe, u64 xm)
 		ieee754_setcx(IEEE754_INEXACT);
 		/* -O can be table indexed by (rm,sn) */
 		switch (ieee754_csr.rm) {
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			return ieee754dp_inf(sn);
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			return ieee754dp_max(sn);
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if (sn == 0)
 				return ieee754dp_inf(0);
 			else
 				return ieee754dp_max(1);
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if (sn == 0)
 				return ieee754dp_max(0);
 			else

arch/mips/math-emu/ieee754sp.c

@@ -67,17 +67,17 @@ static unsigned ieee754sp_get_rounding(int sn, unsigned xm)
 	 */
 	if (xm & (SP_MBIT(3) - 1)) {
 		switch (ieee754_csr.rm) {
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			break;
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			xm += 0x3 + ((xm >> 3) & 1);
 			/* xm += (xm&0x8)?0x4:0x3 */
 			break;
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if (!sn)	/* ?? */
 				xm += 0x8;
 			break;
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if (sn) /* ?? */
 				xm += 0x8;
 			break;
@@ -108,15 +108,15 @@ union ieee754sp ieee754sp_format(int sn, int xe, unsigned xm)
 			ieee754_setcx(IEEE754_INEXACT);
 
 			switch(ieee754_csr.rm) {
-			case IEEE754_RN:
-			case IEEE754_RZ:
+			case FPU_CSR_RN:
+			case FPU_CSR_RZ:
 				return ieee754sp_zero(sn);
-			case IEEE754_RU:      /* toward +Infinity */
+			case FPU_CSR_RU:      /* toward +Infinity */
 				if (sn == 0)
 					return ieee754sp_min(0);
 				else
 					return ieee754sp_zero(1);
-			case IEEE754_RD:      /* toward -Infinity */
+			case FPU_CSR_RD:      /* toward -Infinity */
 				if (sn == 0)
 					return ieee754sp_zero(0);
 				else
@@ -170,16 +170,16 @@ union ieee754sp ieee754sp_format(int sn, int xe, unsigned xm)
 		ieee754_setcx(IEEE754_INEXACT);
 		/* -O can be table indexed by (rm,sn) */
 		switch (ieee754_csr.rm) {
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			return ieee754sp_inf(sn);
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			return ieee754sp_max(sn);
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if (sn == 0)
 				return ieee754sp_inf(0);
 			else
 				return ieee754sp_max(1);
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if (sn == 0)
 				return ieee754sp_max(0);
 			else

arch/mips/math-emu/sp_add.c

@@ -91,7 +91,7 @@ union ieee754sp ieee754sp_add(union ieee754sp x, union ieee754sp y)
 		if (xs == ys)
 			return x;
 		else
-			return ieee754sp_zero(ieee754_csr.rm == IEEE754_RD);
+			return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
 
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
@@ -165,7 +165,7 @@ union ieee754sp ieee754sp_add(union ieee754sp x, union ieee754sp y)
 			xs = ys;
 		}
 		if (xm == 0)
-			return ieee754sp_zero(ieee754_csr.rm == IEEE754_RD);
+			return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
 
 		/*
 		 * Normalize in extended single precision

arch/mips/math-emu/sp_fdp.c

@@ -57,8 +57,8 @@ union ieee754sp ieee754sp_fdp(union ieee754dp x)
 		/* can't possibly be sp representable */
 		ieee754_setcx(IEEE754_UNDERFLOW);
 		ieee754_setcx(IEEE754_INEXACT);
-		if ((ieee754_csr.rm == IEEE754_RU && !xs) ||
-				(ieee754_csr.rm == IEEE754_RD && xs))
+		if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
+				(ieee754_csr.rm == FPU_CSR_RD && xs))
 			return ieee754sp_mind(xs);
 		return ieee754sp_zero(xs);
 

arch/mips/math-emu/sp_sqrt.c

@@ -100,10 +100,10 @@ union ieee754sp ieee754sp_sqrt(union ieee754sp x)
 	if (ix != 0) {
 		ieee754_setcx(IEEE754_INEXACT);
 		switch (ieee754_csr.rm) {
-		case IEEE754_RU:
+		case FPU_CSR_RU:
 			q += 2;
 			break;
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			q += (q & 1);
 			break;
 		}

arch/mips/math-emu/sp_sub.c

@@ -91,7 +91,7 @@ union ieee754sp ieee754sp_sub(union ieee754sp x, union ieee754sp y)
 		if (xs != ys)
 			return x;
 		else
-			return ieee754sp_zero(ieee754_csr.rm == IEEE754_RD);
+			return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
 
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
@@ -165,7 +165,7 @@ union ieee754sp ieee754sp_sub(union ieee754sp x, union ieee754sp y)
 			xs = ys;
 		}
 		if (xm == 0) {
-			if (ieee754_csr.rm == IEEE754_RD)
+			if (ieee754_csr.rm == FPU_CSR_RD)
 				return ieee754sp_zero(1);	/* round negative inf. => sign = -1 */
 			else
 				return ieee754sp_zero(0);	/* other round modes   => sign = 1 */

arch/mips/math-emu/sp_tint.c

@@ -79,17 +79,17 @@ int ieee754sp_tint(union ieee754sp x)
 		}
 		odd = (xm & 0x1) != 0x0;
 		switch (ieee754_csr.rm) {
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			if (round && (sticky || odd))
 				xm++;
 			break;
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			break;
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if ((round || sticky) && !xs)
 				xm++;
 			break;
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if ((round || sticky) && xs)
 				xm++;
 			break;

arch/mips/math-emu/sp_tlong.c

@@ -76,17 +76,17 @@ s64 ieee754sp_tlong(union ieee754sp x)
 		}
 		odd = (xm & 0x1) != 0x0;
 		switch (ieee754_csr.rm) {
-		case IEEE754_RN:
+		case FPU_CSR_RN:
 			if (round && (sticky || odd))
 				xm++;
 			break;
-		case IEEE754_RZ:
+		case FPU_CSR_RZ:
 			break;
-		case IEEE754_RU:	/* toward +Infinity */
+		case FPU_CSR_RU:	/* toward +Infinity */
 			if ((round || sticky) && !xs)
 				xm++;
 			break;
-		case IEEE754_RD:	/* toward -Infinity */
+		case FPU_CSR_RD:	/* toward -Infinity */
 			if ((round || sticky) && xs)
 				xm++;
 			break;