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###################################
# 
#  Copyright 2009, 2010, 2011 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.
# 
#######################################


        .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