xref: /kernel/linux/linux-6.6/arch/xtensa/lib/umodsi3.S (revision 62306a36)
162306a36Sopenharmony_ci/* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0 */
262306a36Sopenharmony_ci#include <linux/linkage.h>
362306a36Sopenharmony_ci#include <asm/asmmacro.h>
462306a36Sopenharmony_ci#include <asm/core.h>
562306a36Sopenharmony_ci
662306a36Sopenharmony_ciENTRY(__umodsi3)
762306a36Sopenharmony_ci
862306a36Sopenharmony_ci	abi_entry_default
962306a36Sopenharmony_ci#if XCHAL_HAVE_DIV32
1062306a36Sopenharmony_ci	remu	a2, a2, a3
1162306a36Sopenharmony_ci#else
1262306a36Sopenharmony_ci	bltui	a3, 2, .Lle_one	/* check if the divisor is <= 1 */
1362306a36Sopenharmony_ci
1462306a36Sopenharmony_ci	do_nsau	a5, a2, a6, a7	/* dividend_shift = nsau (dividend) */
1562306a36Sopenharmony_ci	do_nsau	a4, a3, a6, a7	/* divisor_shift = nsau (divisor) */
1662306a36Sopenharmony_ci	bgeu	a5, a4, .Lspecial
1762306a36Sopenharmony_ci
1862306a36Sopenharmony_ci	sub	a4, a4, a5	/* count = divisor_shift - dividend_shift */
1962306a36Sopenharmony_ci	ssl	a4
2062306a36Sopenharmony_ci	sll	a3, a3		/* divisor <<= count */
2162306a36Sopenharmony_ci
2262306a36Sopenharmony_ci	/* test-subtract-and-shift loop */
2362306a36Sopenharmony_ci#if XCHAL_HAVE_LOOPS
2462306a36Sopenharmony_ci	loopnez	a4, .Lloopend
2562306a36Sopenharmony_ci#endif /* XCHAL_HAVE_LOOPS */
2662306a36Sopenharmony_ci.Lloop:
2762306a36Sopenharmony_ci	bltu	a2, a3, .Lzerobit
2862306a36Sopenharmony_ci	sub	a2, a2, a3
2962306a36Sopenharmony_ci.Lzerobit:
3062306a36Sopenharmony_ci	srli	a3, a3, 1
3162306a36Sopenharmony_ci#if !XCHAL_HAVE_LOOPS
3262306a36Sopenharmony_ci	addi	a4, a4, -1
3362306a36Sopenharmony_ci	bnez	a4, .Lloop
3462306a36Sopenharmony_ci#endif /* !XCHAL_HAVE_LOOPS */
3562306a36Sopenharmony_ci.Lloopend:
3662306a36Sopenharmony_ci
3762306a36Sopenharmony_ci.Lspecial:
3862306a36Sopenharmony_ci	bltu	a2, a3, .Lreturn
3962306a36Sopenharmony_ci	sub	a2, a2, a3	/* subtract once more if dividend >= divisor */
4062306a36Sopenharmony_ci.Lreturn:
4162306a36Sopenharmony_ci	abi_ret_default
4262306a36Sopenharmony_ci
4362306a36Sopenharmony_ci.Lle_one:
4462306a36Sopenharmony_ci	bnez	a3, .Lreturn0
4562306a36Sopenharmony_ci
4662306a36Sopenharmony_ci	/* Divide by zero: Use an illegal instruction to force an exception.
4762306a36Sopenharmony_ci	   The subsequent "DIV0" string can be recognized by the exception
4862306a36Sopenharmony_ci	   handler to identify the real cause of the exception.  */
4962306a36Sopenharmony_ci	ill
5062306a36Sopenharmony_ci	.ascii	"DIV0"
5162306a36Sopenharmony_ci
5262306a36Sopenharmony_ci.Lreturn0:
5362306a36Sopenharmony_ci	movi	a2, 0
5462306a36Sopenharmony_ci#endif /* XCHAL_HAVE_DIV32 */
5562306a36Sopenharmony_ci	abi_ret_default
5662306a36Sopenharmony_ci
5762306a36Sopenharmony_ciENDPROC(__umodsi3)
5862306a36Sopenharmony_ciEXPORT_SYMBOL(__umodsi3)
59