microblaze: Fix __muldi3 function for little-endian.

__muldi3 was written for big endian platforms.
Code contained half word read/write instructions which
are not compatible with little endian cpu.
Asm __muldi3 implementation is replaced by C version.
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/lib/muldi3.S

-#include <linux/linkage.h>
-
-/*
- * Multiply operation for 64 bit integers, for devices with hard multiply
- *	Input :	Operand1[H] in Reg r5
- *		Operand1[L] in Reg r6
- *		Operand2[H] in Reg r7
- *		Operand2[L] in Reg r8
- *	Output: Result[H] in Reg r3
- *		Result[L] in Reg r4
- *
- * Explaination:
- *
- *	Both the input numbers are divided into 16 bit number as follows
- *		op1 = A B C D
- *		op2 = E F G H
- *	result = D * H
- *		 + (C * H + D * G) << 16
- *		 + (B * H + C * G + D * F) << 32
- *		 + (A * H + B * G + C * F + D * E) << 48
- *
- *	Only 64 bits of the output are considered
- */
-
-	.text
-	.globl	__muldi3
-	.type __muldi3, @function
-	.ent __muldi3
-
-__muldi3:
-	addi	r1, r1, -40
-
-/* Save the input operands on the caller's stack */
-	swi	r5, r1, 44
-	swi	r6, r1, 48
-	swi	r7, r1, 52
-	swi	r8, r1, 56
-
-/* Store all the callee saved registers */
-	sw	r20, r1, r0
-	swi	r21, r1, 4
-	swi	r22, r1, 8
-	swi	r23, r1, 12
-	swi	r24, r1, 16
-	swi	r25, r1, 20
-	swi	r26, r1, 24
-	swi	r27, r1, 28
-
-/* Load all the 16 bit values for A thru H */
-	lhui	r20, r1, 44 /* A */
-	lhui	r21, r1, 46 /* B */
-	lhui	r22, r1, 48 /* C */
-	lhui	r23, r1, 50 /* D */
-	lhui	r24, r1, 52 /* E */
-	lhui	r25, r1, 54 /* F */
-	lhui	r26, r1, 56 /* G */
-	lhui	r27, r1, 58 /* H */
-
-/* D * H ==> LSB of the result on stack ==> Store1 */
-	mul	r9, r23, r27
-	swi	r9, r1, 36 /* Pos2 and Pos3 */
-
-/* Hi (Store1) + C * H + D * G ==> Store2 ==> Pos1 and Pos2 */
-/* Store the carry generated in position 2 for Pos 3 */
-	lhui	r11, r1, 36 /* Pos2 */
-	mul	r9, r22, r27 /* C * H */
-	mul	r10, r23, r26 /* D * G */
-	add	r9, r9, r10
-	addc	r12, r0, r0
-	add	r9, r9, r11
-	addc	r12, r12, r0 /* Store the Carry */
-	shi	r9, r1, 36 /* Store Pos2 */
-	swi	r9, r1, 32
-	lhui	r11, r1, 32
-	shi	r11, r1, 34 /* Store Pos1 */
-
-/* Hi (Store2) + B * H + C * G + D * F ==> Store3 ==> Pos0 and Pos1 */
-	mul	r9, r21, r27 /* B * H */
-	mul	r10, r22, r26 /* C * G */
-	mul	r7, r23, r25 /* D * F */
-	add	r9, r9, r11
-	add	r9, r9, r10
-	add	r9, r9, r7
-	swi	r9, r1, 32 /* Pos0 and Pos1 */
-
-/* Hi (Store3) + A * H + B * G + C * F + D * E ==> Store3 ==> Pos0 */
-	lhui	r11, r1, 32 /* Pos0 */
-	mul	r9, r20, r27 /* A * H */
-	mul	r10, r21, r26 /* B * G */
-	mul	r7, r22, r25 /* C * F */
-	mul	r8, r23, r24 /* D * E */
-	add	r9, r9, r11
-	add 	r9, r9, r10
-	add	r9, r9, r7
-	add	r9, r9, r8
-	sext16	r9, r9 /* Sign extend the MSB */
-	shi	r9, r1, 32
-
-/* Move results to r3 and r4 */
-	lhui	r3, r1, 32
-	add	r3, r3, r12
-	shi	r3, r1, 32
-	lwi	r3, r1, 32 /* Hi Part */
-	lwi	r4, r1, 36 /* Lo Part */
-
-/* Restore Callee saved registers */
-	lw	r20, r1, r0
-	lwi	r21, r1, 4
-	lwi	r22, r1, 8
-	lwi	r23, r1, 12
-	lwi	r24, r1, 16
-	lwi	r25, r1, 20
-	lwi	r26, r1, 24
-	lwi	r27, r1, 28
-
-/* Restore Frame and return */
-	rtsd	r15, 8
-	addi	r1, r1, 40
-
-.size __muldi3, . - __muldi3
-.end __muldi3

arch/microblaze/lib/muldi3.c

+#include <linux/module.h>
+
+#include "libgcc.h"
+
+#define DWtype long long
+#define UWtype unsigned long
+#define UHWtype unsigned short
+
+#define W_TYPE_SIZE 32
+
+#define __ll_B ((UWtype) 1 << (W_TYPE_SIZE / 2))
+#define __ll_lowpart(t) ((UWtype) (t) & (__ll_B - 1))
+#define __ll_highpart(t) ((UWtype) (t) >> (W_TYPE_SIZE / 2))
+
+/* If we still don't have umul_ppmm, define it using plain C.  */
+#if !defined(umul_ppmm)
+#define umul_ppmm(w1, w0, u, v)						\
+	do {								\
+		UWtype __x0, __x1, __x2, __x3;				\
+		UHWtype __ul, __vl, __uh, __vh;				\
+									\
+		__ul = __ll_lowpart(u);					\
+		__uh = __ll_highpart(u);				\
+		__vl = __ll_lowpart(v);					\
+		__vh = __ll_highpart(v);				\
+									\
+		__x0 = (UWtype) __ul * __vl;				\
+		__x1 = (UWtype) __ul * __vh;				\
+		__x2 = (UWtype) __uh * __vl;				\
+		__x3 = (UWtype) __uh * __vh;				\
+									\
+		__x1 += __ll_highpart(__x0); /* this can't give carry */\
+		__x1 += __x2; /* but this indeed can */			\
+		if (__x1 < __x2) /* did we get it? */			\
+		__x3 += __ll_B; /* yes, add it in the proper pos */	\
+									\
+		(w1) = __x3 + __ll_highpart(__x1);			\
+		(w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\
+	} while (0)
+#endif
+
+#if !defined(__umulsidi3)
+#define __umulsidi3(u, v) ({				\
+	DWunion __w;					\
+	umul_ppmm(__w.s.high, __w.s.low, u, v);		\
+	__w.ll;						\
+	})
+#endif
+
+DWtype __muldi3(DWtype u, DWtype v)
+{
+	const DWunion uu = {.ll = u};
+	const DWunion vv = {.ll = v};
+	DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)};
+
+	w.s.high += ((UWtype) uu.s.low * (UWtype) vv.s.high
+		+ (UWtype) uu.s.high * (UWtype) vv.s.low);
+
+	return w.ll;
+}