audk/ArmPkg/Library/CompilerIntrinsicsLib/Arm/clzsi2.S

50 lines
1.1 KiB
ArmAsm

#------------------------------------------------------------------------------
#
# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
#
# SPDX-License-Identifier: BSD-2-Clause-Patent
#
#------------------------------------------------------------------------------
#include <AsmMacroIoLib.h>
ASM_FUNC(__clzsi2)
@ frame_needed = 1, uses_anonymous_args = 0
stmfd sp!, {r7, lr}
add r7, sp, #0
movs r3, r0, lsr #16
movne r3, #16
moveq r3, #0
movne r9, #0
moveq r9, #16
mov r3, r0, lsr r3
tst r3, #65280
movne r0, #8
moveq r0, #0
movne lr, #0
moveq lr, #8
mov r3, r3, lsr r0
tst r3, #240
movne r0, #4
moveq r0, #0
movne ip, #0
moveq ip, #4
mov r3, r3, lsr r0
tst r3, #12
movne r0, #2
moveq r0, #0
movne r1, #0
moveq r1, #2
mov r2, r3, lsr r0
add r3, lr, r9
add r0, r3, ip
add r1, r0, r1
mov r0, r2, lsr #1
eor r0, r0, #1
ands r0, r0, #1
mvnne r0, #0
rsb r3, r2, #2
and r0, r0, r3
add r0, r1, r0
ldmfd sp!, {r7, pc}