1 files changed, 73 insertions, 0 deletions

diff --git a/arch/microblaze/lib/modsi3.S b/arch/microblaze/lib/modsi3.S
new file mode 100644
index 000000000000..84e0bee6e8c7
--- /dev/null
+++ b/arch/microblaze/lib/modsi3.S
@@ -0,0 +1,73 @@
+#include <linux/linkage.h>
+
+/*
+* modulo operation for 32 bit integers.
+*       Input : op1 in Reg r5
+*               op2 in Reg r6
+*       Output: op1 mod op2 in Reg r3
+*/
+
+        .text
+        .globl  __modsi3
+        .type __modsi3,  @function
+        .ent __modsi3
+
+__modsi3:
+        .frame  r1, 0, r15
+
+        addik   r1, r1, -16
+        swi     r28, r1, 0
+        swi     r29, r1, 4
+        swi     r30, r1, 8
+        swi     r31, r1, 12
+
+        beqi    r6, div_by_zero /* div_by_zero division error */
+        beqi    r5, result_is_zero /* result is zero */
+        bgeid   r5, r5_pos
+        /* get the sign of the result [ depends only on the first arg] */
+        add     r28, r5, r0
+        rsubi   r5, r5, 0        /* make r5 positive */
+r5_pos:
+        bgei    r6, r6_pos
+        rsubi   r6, r6, 0        /* make r6 positive */
+r6_pos:
+        addik   r3, r0, 0 /* clear mod */
+        addik   r30, r0, 0 /* clear div */
+        addik   r29, r0, 32 /* initialize the loop count */
+/* first part try to find the first '1' in the r5 */
+div1:
+        add     r5, r5, r5 /* left shift logical r5 */
+        bgeid   r5, div1
+        addik   r29, r29, -1
+div2:
+        /* left shift logical r5 get the '1' into the carry */
+        add     r5, r5, r5
+        addc    r3, r3, r3 /* move that bit into the mod register */
+        rsub    r31, r6, r3 /* try to subtract (r30 a r6) */
+        blti    r31, mod_too_small
+        /* move the r31 to mod since the result was positive */
+        or      r3, r0, r31
+        addik   r30, r30, 1
+mod_too_small:
+        addik   r29, r29, -1
+        beqi    r29, loop_end
+        add     r30, r30, r30 /* shift in the '1' into div */
+        bri     div2 /* div2 */
+loop_end:
+        bgei    r28, return_here
+        brid    return_here
+        rsubi   r3, r3, 0 /* negate the result */
+div_by_zero:
+result_is_zero:
+        or      r3, r0, r0 /* set result to 0 [both mod as well as div are 0] */
+return_here:
+/* restore values of csrs and that of r3 and the divisor and the dividend */
+        lwi     r28, r1, 0
+        lwi     r29, r1, 4
+        lwi     r30, r1, 8
+        lwi     r31, r1, 12
+        rtsd    r15, 8
+        addik   r1, r1, 16
+
+.size __modsi3,  . - __modsi3
+.end __modsi3