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###################################
#
# Copyright (C) 2009-2022 Free Software Foundation, Inc.
#
# Contributed by Michael Eager <eager@eagercon.com>.
#
# This file is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 3, or (at your option) any
# later version.
#
# GCC is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
# License for more details.
#
# Under Section 7 of GPL version 3, you are granted additional
# permissions described in the GCC Runtime Library Exception, version
# 3.1, as published by the Free Software Foundation.
#
# You should have received a copy of the GNU General Public License and
# a copy of the GCC Runtime Library Exception along with this program;
# see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
# <http://www.gnu.org/licenses/>.
#
# modsi3.S
#
# modulo operation for 64 bit integers.
#
#######################################
/* An executable stack is *not* required for these functions. */
#ifdef __linux__
.section .note.GNU-stack,"",%progbits
.previous
#endif
.globl __moddi3
.ent __moddi3
__moddi3:
.frame r1,0,r15
#Change the stack pointer value and Save callee saved regs
addik r1,r1,-24
swi r25,r1,0
swi r26,r1,4
swi r27,r1,8 # used for sign
swi r28,r1,12 # used for loop count
swi r29,r1,16 # Used for div value High
swi r30,r1,20 # Used for div value Low
#Check for Zero Value in the divisor/dividend
OR r9,r5,r6 # Check for the op1 being zero
BEQID r9,$LaResult_Is_Zero # Result is zero
OR r9,r7,r8 # Check for the dividend being zero
BEQI r9,$LaDiv_By_Zero # Div_by_Zero # Division Error
BGEId r5,$La1_Pos
XOR r27,r5,r7 # Get the sign of the result
RSUBI r6,r6,0 # Make dividend positive
RSUBIC r5,r5,0 # Make dividend positive
$La1_Pos:
BGEI r7,$La2_Pos
RSUBI r8,r8,0 # Make Divisor Positive
RSUBIC r9,r9,0 # Make Divisor Positive
$La2_Pos:
ADDIK r4,r0,0 # Clear mod low
ADDIK r3,r0,0 # Clear mod high
ADDIK r29,r0,0 # clear div high
ADDIK r30,r0,0 # clear div low
ADDIK r28,r0,64 # Initialize the loop count
# First part try to find the first '1' in the r5/r6
$LaDIV1:
ADD r6,r6,r6
ADDC r5,r5,r5 # left shift logical r5
BGEID r5,$LaDIV1
ADDIK r28,r28,-1
$LaDIV2:
ADD r6,r6,r6
ADDC r5,r5,r5 # left shift logical r5/r6 get the '1' into the Carry
ADDC r4,r4,r4 # Move that bit into the Mod register
ADDC r3,r3,r3 # Move carry into high mod register
rsub r18,r7,r3 # Compare the High Parts of Mod and Divisor
bnei r18,$L_High_EQ
rsub r18,r6,r4 # Compare Low Parts only if Mod[h] == Divisor[h]
$L_High_EQ:
rSUB r26,r8,r4 # Subtract divisor[L] from Mod[L]
rsubc r25,r7,r3 # Subtract divisor[H] from Mod[H]
BLTi r25,$LaMOD_TOO_SMALL
OR r3,r0,r25 # move r25 to mod [h]
OR r4,r0,r26 # move r26 to mod [l]
ADDI r30,r30,1
ADDC r29,r29,r0
$LaMOD_TOO_SMALL:
ADDIK r28,r28,-1
BEQi r28,$LaLOOP_END
ADD r30,r30,r30 # Shift in the '1' into div [low]
ADDC r29,r29,r29 # Move the carry generated into high
BRI $LaDIV2 # Div2
$LaLOOP_END:
BGEI r27,$LaRETURN_HERE
rsubi r30,r30,0
rsubc r29,r29,r0
BRI $LaRETURN_HERE
$LaDiv_By_Zero:
$LaResult_Is_Zero:
or r29,r0,r0 # set result to 0 [High]
or r30,r0,r0 # set result to 0 [Low]
$LaRETURN_HERE:
# Restore values of CSRs and that of r29 and the divisor and the dividend
lwi r25,r1,0
lwi r26,r1,4
lwi r27,r1,8
lwi r28,r1,12
lwi r29,r1,16
lwi r30,r1,20
rtsd r15,8
addik r1,r1,24
.end __moddi3