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Diffstat (limited to 'arch/microblaze/lib/umodsi3.S')
-rw-r--r-- | arch/microblaze/lib/umodsi3.S | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/arch/microblaze/lib/umodsi3.S b/arch/microblaze/lib/umodsi3.S new file mode 100644 index 000000000000..17d16bafae58 --- /dev/null +++ b/arch/microblaze/lib/umodsi3.S | |||
@@ -0,0 +1,86 @@ | |||
1 | #include <linux/linkage.h> | ||
2 | |||
3 | /* | ||
4 | * Unsigned modulo operation for 32 bit integers. | ||
5 | * Input : op1 in Reg r5 | ||
6 | * op2 in Reg r6 | ||
7 | * Output: op1 mod op2 in Reg r3 | ||
8 | */ | ||
9 | |||
10 | .text | ||
11 | .globl __umodsi3 | ||
12 | .type __umodsi3, @function | ||
13 | .ent __umodsi3 | ||
14 | |||
15 | __umodsi3: | ||
16 | .frame r1, 0, r15 | ||
17 | |||
18 | addik r1, r1, -12 | ||
19 | swi r29, r1, 0 | ||
20 | swi r30, r1, 4 | ||
21 | swi r31, r1, 8 | ||
22 | |||
23 | beqi r6, div_by_zero /* div_by_zero - division error */ | ||
24 | beqid r5, result_is_zero /* result is zero */ | ||
25 | addik r3, r0, 0 /* clear div */ | ||
26 | addik r30, r0, 0 /* clear mod */ | ||
27 | addik r29, r0, 32 /* initialize the loop count */ | ||
28 | |||
29 | /* check if r6 and r5 are equal /* if yes, return 0 */ | ||
30 | rsub r18, r5, r6 | ||
31 | beqi r18, return_here | ||
32 | |||
33 | /* check if (uns)r6 is greater than (uns)r5. in that case, just return r5 */ | ||
34 | xor r18, r5, r6 | ||
35 | bgeid r18, 16 | ||
36 | addik r3, r5, 0 | ||
37 | blti r6, return_here | ||
38 | bri $lcheckr6 | ||
39 | rsub r18, r5, r6 /* microblazecmp */ | ||
40 | bgti r18, return_here | ||
41 | |||
42 | /* if r6 [bit 31] is set, then return result as r5-r6 */ | ||
43 | $lcheckr6: | ||
44 | bgtid r6, div0 | ||
45 | addik r3, r0, 0 | ||
46 | addik r18, r0, 0x7fffffff | ||
47 | and r5, r5, r18 | ||
48 | and r6, r6, r18 | ||
49 | brid return_here | ||
50 | rsub r3, r6, r5 | ||
51 | /* first part: try to find the first '1' in the r5 */ | ||
52 | div0: | ||
53 | blti r5, div2 | ||
54 | div1: | ||
55 | add r5, r5, r5 /* left shift logical r5 */ | ||
56 | bgeid r5, div1 | ||
57 | addik r29, r29, -1 | ||
58 | div2: | ||
59 | /* left shift logical r5 get the '1' into the carry */ | ||
60 | add r5, r5, r5 | ||
61 | addc r3, r3, r3 /* move that bit into the mod register */ | ||
62 | rsub r31, r6, r3 /* try to subtract (r3 a r6) */ | ||
63 | blti r31, mod_too_small | ||
64 | /* move the r31 to mod since the result was positive */ | ||
65 | or r3, r0, r31 | ||
66 | addik r30, r30, 1 | ||
67 | mod_too_small: | ||
68 | addik r29, r29, -1 | ||
69 | beqi r29, loop_end | ||
70 | add r30, r30, r30 /* shift in the '1' into div */ | ||
71 | bri div2 /* div2 */ | ||
72 | loop_end: | ||
73 | bri return_here | ||
74 | div_by_zero: | ||
75 | result_is_zero: | ||
76 | or r3, r0, r0 /* set result to 0 */ | ||
77 | return_here: | ||
78 | /* restore values of csrs and that of r3 and the divisor and the dividend */ | ||
79 | lwi r29, r1, 0 | ||
80 | lwi r30, r1, 4 | ||
81 | lwi r31, r1, 8 | ||
82 | rtsd r15, 8 | ||
83 | addik r1, r1, 12 | ||
84 | |||
85 | .size __umodsi3, . - __umodsi3 | ||
86 | .end __umodsi3 | ||