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1/* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0 */
2#include <linux/linkage.h>
3#include <asm/asmmacro.h>
4#include <asm/core.h>
5
6ENTRY(__modsi3)
7
8 abi_entry_default
9#if XCHAL_HAVE_DIV32
10 rems a2, a2, a3
11#else
12 mov a7, a2 /* save original (signed) dividend */
13 do_abs a2, a2, a4 /* udividend = abs (dividend) */
14 do_abs a3, a3, a4 /* udivisor = abs (divisor) */
15 bltui a3, 2, .Lle_one /* check if udivisor <= 1 */
16 do_nsau a5, a2, a6, a8 /* udividend_shift = nsau (udividend) */
17 do_nsau a4, a3, a6, a8 /* udivisor_shift = nsau (udivisor) */
18 bgeu a5, a4, .Lspecial
19
20 sub a4, a4, a5 /* count = udivisor_shift - udividend_shift */
21 ssl a4
22 sll a3, a3 /* udivisor <<= count */
23
24 /* test-subtract-and-shift loop */
25#if XCHAL_HAVE_LOOPS
26 loopnez a4, .Lloopend
27#endif /* XCHAL_HAVE_LOOPS */
28.Lloop:
29 bltu a2, a3, .Lzerobit
30 sub a2, a2, a3
31.Lzerobit:
32 srli a3, a3, 1
33#if !XCHAL_HAVE_LOOPS
34 addi a4, a4, -1
35 bnez a4, .Lloop
36#endif /* !XCHAL_HAVE_LOOPS */
37.Lloopend:
38
39.Lspecial:
40 bltu a2, a3, .Lreturn
41 sub a2, a2, a3 /* subtract again if udividend >= udivisor */
42.Lreturn:
43 bgez a7, .Lpositive
44 neg a2, a2 /* if (dividend < 0), return -udividend */
45.Lpositive:
46 abi_ret_default
47
48.Lle_one:
49 bnez a3, .Lreturn0
50
51 /* Divide by zero: Use an illegal instruction to force an exception.
52 The subsequent "DIV0" string can be recognized by the exception
53 handler to identify the real cause of the exception. */
54 ill
55 .ascii "DIV0"
56
57.Lreturn0:
58 movi a2, 0
59#endif /* XCHAL_HAVE_DIV32 */
60 abi_ret_default
61
62ENDPROC(__modsi3)
63EXPORT_SYMBOL(__modsi3)
64
65#if !XCHAL_HAVE_NSA
66 .section .rodata
67 .align 4
68 .global __nsau_data
69 .type __nsau_data, @object
70__nsau_data:
71 .byte 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4
72 .byte 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3
73 .byte 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
74 .byte 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
75 .byte 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
76 .byte 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
77 .byte 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
78 .byte 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
79 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
80 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
81 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
82 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
83 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
84 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
85 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
86 .byte 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
87 .size __nsau_data, . - __nsau_data
88#endif /* !XCHAL_HAVE_NSA */