Syncboot/efi/lib/arm/div.S
Curle 4300dc655c Add EFI documentation, libraries and includes.
The lib/inc folders are from the GNU-EFI project.
The documentation is from the uefi.org site.

Yes, I know there are duplicate includes. I have a plan for them.
2019-07-17 15:11:52 +01:00

156 lines
3.7 KiB
ArmAsm

#------------------------------------------------------------------------------
#
# Copyright (c) 2011, ARM. All rights reserved.<BR>
#
# This program and the accompanying materials
# are licensed and made available under the terms and conditions of the BSD License
# which accompanies this distribution. The full text of the license may be found at
# http://opensource.org/licenses/bsd-license.php
#
# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#
#------------------------------------------------------------------------------
#include "edk2asm.h"
.text
.align 2
GCC_ASM_EXPORT(__aeabi_uidiv)
GCC_ASM_EXPORT(__aeabi_uidivmod)
GCC_ASM_EXPORT(__aeabi_idiv)
GCC_ASM_EXPORT(__aeabi_idivmod)
# AREA Math, CODE, READONLY
#
#UINT32
#EFIAPI
#__aeabi_uidivmode (
# IN UINT32 Dividen
# IN UINT32 Divisor
# );
#
ASM_PFX(__aeabi_uidiv):
ASM_PFX(__aeabi_uidivmod):
rsbs r12, r1, r0, LSR #4
mov r2, #0
bcc ASM_PFX(__arm_div4)
rsbs r12, r1, r0, LSR #8
bcc ASM_PFX(__arm_div8)
mov r3, #0
b ASM_PFX(__arm_div_large)
#
#INT32
#EFIAPI
#__aeabi_idivmode (
# IN INT32 Dividen
# IN INT32 Divisor
# );
#
ASM_PFX(__aeabi_idiv):
ASM_PFX(__aeabi_idivmod):
orrs r12, r0, r1
bmi ASM_PFX(__arm_div_negative)
rsbs r12, r1, r0, LSR #1
mov r2, #0
bcc ASM_PFX(__arm_div1)
rsbs r12, r1, r0, LSR #4
bcc ASM_PFX(__arm_div4)
rsbs r12, r1, r0, LSR #8
bcc ASM_PFX(__arm_div8)
mov r3, #0
b ASM_PFX(__arm_div_large)
ASM_PFX(__arm_div8):
rsbs r12, r1, r0, LSR #7
subcs r0, r0, r1, LSL #7
adc r2, r2, r2
rsbs r12, r1, r0,LSR #6
subcs r0, r0, r1, LSL #6
adc r2, r2, r2
rsbs r12, r1, r0, LSR #5
subcs r0, r0, r1, LSL #5
adc r2, r2, r2
rsbs r12, r1, r0, LSR #4
subcs r0, r0, r1, LSL #4
adc r2, r2, r2
ASM_PFX(__arm_div4):
rsbs r12, r1, r0, LSR #3
subcs r0, r0, r1, LSL #3
adc r2, r2, r2
rsbs r12, r1, r0, LSR #2
subcs r0, r0, r1, LSL #2
adcs r2, r2, r2
rsbs r12, r1, r0, LSR #1
subcs r0, r0, r1, LSL #1
adc r2, r2, r2
ASM_PFX(__arm_div1):
subs r1, r0, r1
movcc r1, r0
adc r0, r2, r2
bx r14
ASM_PFX(__arm_div_negative):
ands r2, r1, #0x80000000
rsbmi r1, r1, #0
eors r3, r2, r0, ASR #32
rsbcs r0, r0, #0
rsbs r12, r1, r0, LSR #4
bcc label1
rsbs r12, r1, r0, LSR #8
bcc label2
ASM_PFX(__arm_div_large):
lsl r1, r1, #6
rsbs r12, r1, r0, LSR #8
orr r2, r2, #0xfc000000
bcc label2
lsl r1, r1, #6
rsbs r12, r1, r0, LSR #8
orr r2, r2, #0x3f00000
bcc label2
lsl r1, r1, #6
rsbs r12, r1, r0, LSR #8
orr r2, r2, #0xfc000
orrcs r2, r2, #0x3f00
lslcs r1, r1, #6
rsbs r12, r1, #0
bcs ASM_PFX(__aeabi_idiv0)
label3:
lsrcs r1, r1, #6
label2:
rsbs r12, r1, r0, LSR #7
subcs r0, r0, r1, LSL #7
adc r2, r2, r2
rsbs r12, r1, r0, LSR #6
subcs r0, r0, r1, LSL #6
adc r2, r2, r2
rsbs r12, r1, r0, LSR #5
subcs r0, r0, r1, LSL #5
adc r2, r2, r2
rsbs r12, r1, r0, LSR #4
subcs r0, r0, r1, LSL #4
adc r2, r2, r2
label1:
rsbs r12, r1, r0, LSR #3
subcs r0, r0, r1, LSL #3
adc r2, r2, r2
rsbs r12, r1, r0, LSR #2
subcs r0, r0, r1, LSL #2
adcs r2, r2, r2
bcs label3
rsbs r12, r1, r0, LSR #1
subcs r0, r0, r1, LSL #1
adc r2, r2, r2
subs r1, r0, r1
movcc r1, r0
adc r0, r2, r2
asrs r3, r3, #31
rsbmi r0, r0, #0
rsbcs r1, r1, #0
bx r14
@ What to do about division by zero? For now, just return.
ASM_PFX(__aeabi_idiv0):
bx r14