1 .macro ARM_MOD_BODY dividend, divisor, order, spare
3 #if __LINUX_ARM_ARCH__ >= 5
7 sub \order, \order, \spare
8 mov \divisor, \divisor, lsl \order
14 @ Unless the divisor is very big, shift it up in multiples of
15 @ four bits, since this is the amount of unwinding in the main
16 @ division loop. Continue shifting until the divisor is
17 @ larger than the dividend.
18 1: cmp \divisor, #0x10000000
19 cmplo \divisor, \dividend
20 movlo \divisor, \divisor, lsl #4
21 addlo \order, \order, #4
24 @ For very big divisors, we must shift it a bit at a time, or
25 @ we will be in danger of overflowing.
26 1: cmp \divisor, #0x80000000
27 cmplo \divisor, \dividend
28 movlo \divisor, \divisor, lsl #1
29 addlo \order, \order, #1
34 @ Perform all needed substractions to keep only the reminder.
35 @ Do comparisons in batch of 4 first.
36 subs \order, \order, #3 @ yes, 3 is intended here
39 1: cmp \dividend, \divisor
40 subhs \dividend, \dividend, \divisor
41 cmp \dividend, \divisor, lsr #1
42 subhs \dividend, \dividend, \divisor, lsr #1
43 cmp \dividend, \divisor, lsr #2
44 subhs \dividend, \dividend, \divisor, lsr #2
45 cmp \dividend, \divisor, lsr #3
46 subhs \dividend, \dividend, \divisor, lsr #3
48 mov \divisor, \divisor, lsr #4
49 subges \order, \order, #4
56 @ Either 1, 2 or 3 comparison/substractions are left.
60 cmp \dividend, \divisor
61 subhs \dividend, \dividend, \divisor
62 mov \divisor, \divisor, lsr #1
63 3: cmp \dividend, \divisor
64 subhs \dividend, \dividend, \divisor
65 mov \divisor, \divisor, lsr #1
66 4: cmp \dividend, \divisor
67 subhs \dividend, \dividend, \divisor
76 rsbmi r1, r1, #0 @ loops below use unsigned.
77 movs ip, r0 @ preserve sign of dividend
78 rsbmi r0, r0, #0 @ if negative make positive
79 subs r2, r1, #1 @ compare divisor with 1
80 cmpne r0, r1 @ compare dividend with divisor
82 tsthi r1, r2 @ see if divisor is power of 2
86 ARM_MOD_BODY r0, r1, r2, r3
97 mov r0, #0 @ About as wrong as it could be.