audk/ArmPkg/Library/CompilerIntrinsicsLib/Arm/ctzsi2.S

42 lines
895 B
ArmAsm

#------------------------------------------------------------------------------
#
# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
#
# SPDX-License-Identifier: BSD-2-Clause-Patent
#
#------------------------------------------------------------------------------
#include <AsmMacroIoLib.h>
ASM_FUNC(__ctzsi2)
uxth r3, r0
cmp r3, #0
moveq ip, #16
movne ip, #0
@ lr needed for prologue
mov r0, r0, lsr ip
tst r0, #255
movne r3, #0
moveq r3, #8
mov r0, r0, lsr r3
tst r0, #15
movne r1, #0
moveq r1, #4
add r3, r3, ip
mov r0, r0, lsr r1
tst r0, #3
movne r2, #0
moveq r2, #2
add r3, r3, r1
mov r0, r0, lsr r2
and r0, r0, #3
add r2, r3, r2
eor r3, r0, #1
mov r0, r0, lsr #1
ands r3, r3, #1
mvnne r3, #0
rsb r0, r0, #2
and r0, r3, r0
add r0, r2, r0
bx lr