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 */
89