diff options
Diffstat (limited to 'sys/libkern/arm/ldivmod.S')
| -rw-r--r-- | sys/libkern/arm/ldivmod.S | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/sys/libkern/arm/ldivmod.S b/sys/libkern/arm/ldivmod.S new file mode 100644 index 0000000..a88db54 --- /dev/null +++ b/sys/libkern/arm/ldivmod.S @@ -0,0 +1,67 @@ +/* + * Copyright (C) 2012 Andrew Turner + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + */ + +#include <machine/asm.h> +__FBSDID("$FreeBSD$"); + +#ifdef __ARM_EABI__ + +/* + * These calculate: + * q = n / m + * With a remainer r. + * + * They take n in {r0, r1} and m in {r2, r3} then pass them into the + * helper function. The hepler functions return q in {r0, r1} as + * required by the API spec however r is returned on the stack. The + * ABI required us to return r in {r2, r3}. + * + * We need to allocate 8 bytes on the stack to store r, the link + * register, and a pointer to the space where the helper function + * will write r to. After returning from the helper fuinction we load + * the old link register and r from the stack and return. + */ +ENTRY_NP(__aeabi_ldivmod) + sub sp, sp, #8 /* Space for the remainder */ + stmfd sp!, {sp, lr} /* Save a pointer to the above space and lr */ + bl PIC_SYM(_C_LABEL(__kern_ldivmod), PLT) + ldr lr, [sp, #4] /* Restore lr */ + add sp, sp, #8 /* Move sp to the remainder value */ + ldmfd sp!, {r2, r3} /* Load the remainder */ + RET + +ENTRY_NP(__aeabi_uldivmod) + sub sp, sp, #8 /* Space for the remainder */ + stmfd sp!, {sp, lr} /* Save a pointer to the above space and lr */ + bl PIC_SYM(_C_LABEL(__qdivrem), PLT) + ldr lr, [sp, #4] /* Restore lr */ + add sp, sp, #8 /* Move sp to the remainder value */ + ldmfd sp!, {r2, r3} /* Load the remainder */ + RET + +#endif + |
