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+
+.macro ARM_MOD_BODY dividend, divisor, order, spare
+
+#if __LINUX_ARM_ARCH__ >= 5
+
+ clz \order, \divisor
+ clz \spare, \dividend
+ sub \order, \order, \spare
+ mov \divisor, \divisor, lsl \order
+
+#else
+
+ mov \order, #0
+
+ @ Unless the divisor is very big, shift it up in multiples of
+ @ four bits, since this is the amount of unwinding in the main
+ @ division loop. Continue shifting until the divisor is
+ @ larger than the dividend.
+1: cmp \divisor, #0x10000000
+ cmplo \divisor, \dividend
+ movlo \divisor, \divisor, lsl #4
+ addlo \order, \order, #4
+ blo 1b
+
+ @ For very big divisors, we must shift it a bit at a time, or
+ @ we will be in danger of overflowing.
+1: cmp \divisor, #0x80000000
+ cmplo \divisor, \dividend
+ movlo \divisor, \divisor, lsl #1
+ addlo \order, \order, #1
+ blo 1b
+
+#endif
+
+ @ Perform all needed substractions to keep only the reminder.
+ @ Do comparisons in batch of 4 first.
+ subs \order, \order, #3 @ yes, 3 is intended here
+ blt 2f
+
+1: cmp \dividend, \divisor
+ subhs \dividend, \dividend, \divisor
+ cmp \dividend, \divisor, lsr #1
+ subhs \dividend, \dividend, \divisor, lsr #1
+ cmp \dividend, \divisor, lsr #2
+ subhs \dividend, \dividend, \divisor, lsr #2
+ cmp \dividend, \divisor, lsr #3
+ subhs \dividend, \dividend, \divisor, lsr #3
+ cmp \dividend, #1
+ mov \divisor, \divisor, lsr #4
+ subges \order, \order, #4
+ bge 1b
+
+ tst \order, #3
+ teqne \dividend, #0
+ beq 5f
+
+ @ Either 1, 2 or 3 comparison/substractions are left.
+2: cmn \order, #2
+ blt 4f
+ beq 3f
+ cmp \dividend, \divisor
+ subhs \dividend, \dividend, \divisor
+ mov \divisor, \divisor, lsr #1
+3: cmp \dividend, \divisor
+ subhs \dividend, \dividend, \divisor
+ mov \divisor, \divisor, lsr #1
+4: cmp \dividend, \divisor
+ subhs \dividend, \dividend, \divisor
+5:
+.endm
+
+ .align 5
+.globl __modsi3
+__modsi3:
+ cmp r1, #0
+ beq Ldiv0
+ rsbmi r1, r1, #0 @ loops below use unsigned.
+ movs ip, r0 @ preserve sign of dividend
+ rsbmi r0, r0, #0 @ if negative make positive
+ subs r2, r1, #1 @ compare divisor with 1
+ cmpne r0, r1 @ compare dividend with divisor
+ moveq r0, #0
+ tsthi r1, r2 @ see if divisor is power of 2
+ andeq r0, r0, r2
+ bls 10f
+
+ ARM_MOD_BODY r0, r1, r2, r3
+
+10: cmp ip, #0
+ rsbmi r0, r0, #0
+ mov pc, lr
+
+
+Ldiv0:
+
+ str lr, [sp, #-4]!
+ bl __div0
+ mov r0, #0 @ About as wrong as it could be.
+ ldr pc, [sp], #4