1 files changed, 47 insertions, 0 deletions
diff --git a/lib/arm/divmodsi4.S b/lib/arm/divmodsi4.S
new file mode 100644
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+++ b/lib/arm/divmodsi4.S
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+/*===-- divmodsi4.S - 32-bit signed integer divide and modulus ------------===//
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ *===----------------------------------------------------------------------===//
+ *
+ * This file implements the __divmodsi4 (32-bit signed integer divide and
+ * modulus) function for the ARM architecture.  A naive digit-by-digit
+ * computation is employed for simplicity.
+ *
+ *===----------------------------------------------------------------------===*/
+
+#include "../assembly.h"
+
+#define ESTABLISH_FRAME    \
+    push   {r4-r7, lr}   ;\
+    add     r7,     sp, #12
+#define CLEAR_FRAME_AND_RETURN \
+    pop    {r4-r7, pc}
+
+.syntax unified
+.align 3
+DEFINE_COMPILERRT_FUNCTION(__divmodsi4)
+    ESTABLISH_FRAME
+//  Set aside the sign of the quotient and modulus, and the address for the
+//  modulus.
+    eor     r4,     r0, r1
+    mov     r5,     r0
+    mov     r6,     r2
+//  Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
+    eor     ip,     r0, r0, asr #31
+    eor     lr,     r1, r1, asr #31
+    sub     r0,     ip, r0, asr #31
+    sub     r1,     lr, r1, asr #31
+//  Unsigned divmod:
+    bl      SYMBOL_NAME(__udivmodsi4)
+//  Apply the sign of quotient and modulus
+    ldr     r1,    [r6]
+    eor     r0,     r0, r4, asr #31
+    eor     r1,     r1, r5, asr #31
+    sub     r0,     r0, r4, asr #31
+    sub     r1,     r1, r5, asr #31
+    str     r1,    [r6]
+    CLEAR_FRAME_AND_RETURN