################################### # # Copyright (C) 2009-2020 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 32 bit integers. # Input : op1 in Reg r5 # op2 in Reg r6 # Output: op1 mod op2 in Reg r3 # ####################################### /* An executable stack is *not* required for these functions. */ #ifdef __linux__ .section .note.GNU-stack,"",%progbits .previous #endif .globl __modsi3 .ent __modsi3 .type __modsi3,@function __modsi3: .frame r1,0,r15 addik r1,r1,-16 swi r28,r1,0 swi r29,r1,4 swi r30,r1,8 swi r31,r1,12 BEQI r6,$LaDiv_By_Zero # Div_by_Zero # Division Error BEQI r5,$LaResult_Is_Zero # Result is Zero BGEId r5,$LaR5_Pos ADD r28,r5,r0 # Get the sign of the result [ Depends only on the first arg] RSUBI r5,r5,0 # Make r5 positive $LaR5_Pos: BGEI r6,$LaR6_Pos RSUBI r6,r6,0 # Make r6 positive $LaR6_Pos: ADDIK r3,r0,0 # Clear mod ADDIK r30,r0,0 # clear div BLTId r5,$LaDIV2 # If r5 is still negative (0x80000000), skip # the first bit search. ADDIK r29,r0,32 # Initialize the loop count # First part try to find the first '1' in the r5 $LaDIV1: ADD r5,r5,r5 # left shift logical r5 BGEID r5,$LaDIV1 # ADDIK r29,r29,-1 $LaDIV2: ADD r5,r5,r5 # left shift logical r5 get the '1' into the Carry ADDC r3,r3,r3 # Move that bit into the Mod register rSUB r31,r6,r3 # Try to subtract (r30 a r6) BLTi r31,$LaMOD_TOO_SMALL OR r3,r0,r31 # Move the r31 to mod since the result was positive ADDIK r30,r30,1 $LaMOD_TOO_SMALL: ADDIK r29,r29,-1 BEQi r29,$LaLOOP_END ADD r30,r30,r30 # Shift in the '1' into div BRI $LaDIV2 # Div2 $LaLOOP_END: BGEI r28,$LaRETURN_HERE BRId $LaRETURN_HERE rsubi r3,r3,0 # Negate the result $LaDiv_By_Zero: $LaResult_Is_Zero: or r3,r0,r0 # set result to 0 [Both mod as well as div are 0] $LaRETURN_HERE: # Restore values of CSRs and that of r3 and the divisor and the dividend lwi r28,r1,0 lwi r29,r1,4 lwi r30,r1,8 lwi r31,r1,12 rtsd r15,8 addik r1,r1,16 .end __modsi3 .size __modsi3, . - __modsi3 |