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/* Runtime ABI for the ARM Cortex-M0
* lmul.S: 64 bit multiplication
*
* Copyright (c) 2013 Jörg Mische <bobbl@gmx.de>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
.syntax unified
.text
.thumb
.cpu cortex-m0
@ long long __aeabi_lmul(long long r1:r0, long long r3:r2)
@
@ Multiply r1:r0 and r3:r2 and return the product in r1:r0
@ Can also be used for unsigned long product
@
.thumb_func
.section .text.__aeabi_lmul
.global __aeabi_lmul
__aeabi_lmul:
push {r4, lr}
muls r1, r2
muls r3, r0
adds r1, r3
lsrs r3, r0, #16
lsrs r4, r2, #16
muls r3, r4
adds r1, r3
lsrs r3, r0, #16
uxth r0, r0
uxth r2, r2
muls r3, r2
muls r4, r0
muls r0, r2
movs r2, #0
adds r3, r4
adcs r2, r2
lsls r2, #16
adds r1, r2
lsls r2, r3, #16
lsrs r3, #16
adds r0, r2
adcs r1, r3
pop {r4, pc}
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