xref: /freebsd/sys/libkern/arm/ldivmod.S (revision 685dc743dc3b5645e34836464128e1c0558b404b)
146d741dcSAndrew Turner/*
246d741dcSAndrew Turner * Copyright (C) 2012 Andrew Turner
346d741dcSAndrew Turner * All rights reserved.
446d741dcSAndrew Turner *
546d741dcSAndrew Turner * Redistribution and use in source and binary forms, with or without
646d741dcSAndrew Turner * modification, are permitted provided that the following conditions
746d741dcSAndrew Turner * are met:
846d741dcSAndrew Turner * 1. Redistributions of source code must retain the above copyright
946d741dcSAndrew Turner *    notice, this list of conditions and the following disclaimer.
1046d741dcSAndrew Turner * 2. Redistributions in binary form must reproduce the above copyright
1146d741dcSAndrew Turner *    notice, this list of conditions and the following disclaimer in the
1246d741dcSAndrew Turner *    documentation and/or other materials provided with the distribution.
1346d741dcSAndrew Turner *
1446d741dcSAndrew Turner * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
1546d741dcSAndrew Turner * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1646d741dcSAndrew Turner * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1746d741dcSAndrew Turner * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
1846d741dcSAndrew Turner * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
1946d741dcSAndrew Turner * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2046d741dcSAndrew Turner * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
2146d741dcSAndrew Turner * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
2246d741dcSAndrew Turner * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
2346d741dcSAndrew Turner * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
2446d741dcSAndrew Turner * SUCH DAMAGE.
2546d741dcSAndrew Turner *
2646d741dcSAndrew Turner */
2746d741dcSAndrew Turner
2846d741dcSAndrew Turner#include <machine/asm.h>
2946d741dcSAndrew Turner/*
3046d741dcSAndrew Turner * These calculate:
3146d741dcSAndrew Turner * q = n / m
3246d741dcSAndrew Turner * With a remainer r.
3346d741dcSAndrew Turner *
3446d741dcSAndrew Turner * They take n in {r0, r1} and m in {r2, r3} then pass them into the
3546d741dcSAndrew Turner * helper function. The hepler functions return q in {r0, r1} as
3646d741dcSAndrew Turner * required by the API spec however r is returned on the stack. The
3746d741dcSAndrew Turner * ABI required us to return r in {r2, r3}.
3846d741dcSAndrew Turner *
3946d741dcSAndrew Turner * We need to allocate 8 bytes on the stack to store r, the link
4046d741dcSAndrew Turner * register, and a pointer to the space where the helper function
4146d741dcSAndrew Turner * will write r to. After returning from the helper fuinction we load
4246d741dcSAndrew Turner * the old link register and r from the stack and return.
4346d741dcSAndrew Turner */
4446d741dcSAndrew TurnerENTRY_NP(__aeabi_ldivmod)
4546d741dcSAndrew Turner	sub	sp, sp, #8	/* Space for the remainder */
4646d741dcSAndrew Turner	stmfd	sp!, {sp, lr}	/* Save a pointer to the above space and lr */
4746d741dcSAndrew Turner	bl	PIC_SYM(_C_LABEL(__kern_ldivmod), PLT)
4846d741dcSAndrew Turner	ldr	lr, [sp, #4]	/* Restore lr */
4946d741dcSAndrew Turner	add	sp, sp, #8	/* Move sp to the remainder value */
5046d741dcSAndrew Turner	ldmfd	sp!, {r2, r3}	/* Load the remainder */
5146d741dcSAndrew Turner	RET
52*a2dee2adSAndrew TurnerEND(__aeabi_ldivmod)
5346d741dcSAndrew Turner
5446d741dcSAndrew TurnerENTRY_NP(__aeabi_uldivmod)
5546d741dcSAndrew Turner	sub	sp, sp, #8	/* Space for the remainder */
5646d741dcSAndrew Turner	stmfd	sp!, {sp, lr}	/* Save a pointer to the above space and lr */
5746d741dcSAndrew Turner	bl	PIC_SYM(_C_LABEL(__qdivrem), PLT)
5846d741dcSAndrew Turner	ldr	lr, [sp, #4]	/* Restore lr */
5946d741dcSAndrew Turner	add	sp, sp, #8	/* Move sp to the remainder value */
6046d741dcSAndrew Turner	ldmfd	sp!, {r2, r3}	/* Load the remainder */
6146d741dcSAndrew Turner	RET
62*a2dee2adSAndrew TurnerEND(__aeabi_uldivmod)
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