Retro68/gcc/libgcc/config/riscv/div.S
2017-10-07 02:16:47 +02:00

147 lines
3.3 KiB
ArmAsm

/* Integer division routines for RISC-V.
Copyright (C) 2016-2017 Free Software Foundation, Inc.
This file is part of GCC.
GCC 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/>. */
.text
.align 2
#if __riscv_xlen == 32
/* Our RV64 64-bit routines are equivalent to our RV32 32-bit routines. */
# define __udivdi3 __udivsi3
# define __umoddi3 __umodsi3
# define __divdi3 __divsi3
# define __moddi3 __modsi3
#else
.globl __udivsi3
__udivsi3:
/* Compute __udivdi3(a0 << 32, a1 << 32); cast result to uint32_t. */
sll a0, a0, 32
sll a1, a1, 32
move t0, ra
jal __udivdi3
sext.w a0, a0
jr t0
.globl __umodsi3
__umodsi3:
/* Compute __udivdi3((uint32_t)a0, (uint32_t)a1); cast a1 to uint32_t. */
sll a0, a0, 32
sll a1, a1, 32
srl a0, a0, 32
srl a1, a1, 32
move t0, ra
jal __udivdi3
sext.w a0, a1
jr t0
.globl __modsi3
__modsi3 = __moddi3
.globl __divsi3
__divsi3:
/* Check for special case of INT_MIN/-1. Otherwise, fall into __divdi3. */
li t0, -1
beq a1, t0, .L20
#endif
.globl __divdi3
__divdi3:
bltz a0, .L10
bltz a1, .L11
/* Since the quotient is positive, fall into __udivdi3. */
.globl __udivdi3
__udivdi3:
mv a2, a1
mv a1, a0
li a0, -1
beqz a2, .L5
li a3, 1
bgeu a2, a1, .L2
.L1:
blez a2, .L2
slli a2, a2, 1
slli a3, a3, 1
bgtu a1, a2, .L1
.L2:
li a0, 0
.L3:
bltu a1, a2, .L4
sub a1, a1, a2
or a0, a0, a3
.L4:
srli a3, a3, 1
srli a2, a2, 1
bnez a3, .L3
.L5:
ret
.globl __umoddi3
__umoddi3:
/* Call __udivdi3(a0, a1), then return the remainder, which is in a1. */
move t0, ra
jal __udivdi3
move a0, a1
jr t0
/* Handle negative arguments to __divdi3. */
.L10:
neg a0, a0
bgez a1, .L12 /* Compute __udivdi3(-a0, a1), then negate the result. */
neg a1, a1
j __udivdi3 /* Compute __udivdi3(-a0, -a1). */
.L11: /* Compute __udivdi3(a0, -a1), then negate the result. */
neg a1, a1
.L12:
move t0, ra
jal __udivdi3
neg a0, a0
jr t0
.globl __moddi3
__moddi3:
move t0, ra
bltz a1, .L31
bltz a0, .L32
.L30:
jal __udivdi3 /* The dividend is not negative. */
move a0, a1
jr t0
.L31:
neg a1, a1
bgez a0, .L30
.L32:
neg a0, a0
jal __udivdi3 /* The dividend is hella negative. */
neg a0, a1
jr t0
#if __riscv_xlen == 64
/* continuation of __divsi3 */
.L20:
sll t0, t0, 31
bne a0, t0, __divdi3
ret
#endif