u-boot/arch/arc/lib/libgcc2.c
Alexey Brodkin a67ef280f4 arc: build libgcc in U-Boot
This way we may have very limited set of functions implemented so we
save some space.

Also it allows us to build U-Boot for any ARC core with the same one
toolchain because we don't rely on pre-built libgcc.

For example:
 * we may use little-endian toolchain but build U-Boot for ether
endianess
 * we may use non-multilibbed uClibc toolchain but build U-Boot for
whatever ARC CPU flavour that current GCC supports

Private libgcc built from generic C implementation contributes only 144
bytes to .text section so we don't see significant degradation of size:
--->8---
$ arc-linux-size u-boot.libgcc-prebuilt
   text	   data	    bss	    dec	    hex	filename
 222217	  24912	 214820	 461949	  70c7d	u-boot.libgcc-prebuilt

$ arc-linux-size u-boot.libgcc-private
   text	   data	    bss	    dec	    hex	filename
 222361	  24912	 214820	 462093	  70d0d	u-boot.libgcc-private
--->8---

Also I don't notice visible performance degradation compared to
pre-built libgcc (where at least "*div*" functions are had-written in
assembly) on typical operations of downloading 10Mb uImage over TFTP and
bootm.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
2015-02-09 16:41:20 +03:00

161 lines
2.2 KiB
C

/*
* Copyright (C) 1989-2013 Free Software Foundation, Inc.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include "libgcc2.h"
DWtype
__ashldi3(DWtype u, shift_count_type b)
{
if (b == 0)
return u;
const DWunion uu = {.ll = u};
const shift_count_type bm = W_TYPE_SIZE - b;
DWunion w;
if (bm <= 0) {
w.s.low = 0;
w.s.high = (UWtype)uu.s.low << -bm;
} else {
const UWtype carries = (UWtype) uu.s.low >> bm;
w.s.low = (UWtype)uu.s.low << b;
w.s.high = ((UWtype)uu.s.high << b) | carries;
}
return w.ll;
}
DWtype
__ashrdi3(DWtype u, shift_count_type b)
{
if (b == 0)
return u;
const DWunion uu = {.ll = u};
const shift_count_type bm = W_TYPE_SIZE - b;
DWunion w;
if (bm <= 0) {
/* w.s.high = 1..1 or 0..0 */
w.s.high = uu.s.high >> (W_TYPE_SIZE - 1);
w.s.low = uu.s.high >> -bm;
} else {
const UWtype carries = (UWtype) uu.s.high << bm;
w.s.high = uu.s.high >> b;
w.s.low = ((UWtype)uu.s.low >> b) | carries;
}
return w.ll;
}
DWtype
__lshrdi3(DWtype u, shift_count_type b)
{
if (b == 0)
return u;
const DWunion uu = {.ll = u};
const shift_count_type bm = W_TYPE_SIZE - b;
DWunion w;
if (bm <= 0) {
w.s.high = 0;
w.s.low = (UWtype)uu.s.high >> -bm;
} else {
const UWtype carries = (UWtype)uu.s.high << bm;
w.s.high = (UWtype)uu.s.high >> b;
w.s.low = ((UWtype)uu.s.low >> b) | carries;
}
return w.ll;
}
unsigned long
udivmodsi4(unsigned long num, unsigned long den, int modwanted)
{
unsigned long bit = 1;
unsigned long res = 0;
while (den < num && bit && !(den & (1L<<31))) {
den <<= 1;
bit <<= 1;
}
while (bit) {
if (num >= den) {
num -= den;
res |= bit;
}
bit >>= 1;
den >>= 1;
}
if (modwanted)
return num;
return res;
}
long
__divsi3(long a, long b)
{
int neg = 0;
long res;
if (a < 0) {
a = -a;
neg = !neg;
}
if (b < 0) {
b = -b;
neg = !neg;
}
res = udivmodsi4(a, b, 0);
if (neg)
res = -res;
return res;
}
long
__modsi3(long a, long b)
{
int neg = 0;
long res;
if (a < 0) {
a = -a;
neg = 1;
}
if (b < 0)
b = -b;
res = udivmodsi4(a, b, 1);
if (neg)
res = -res;
return res;
}
long
__udivsi3(long a, long b)
{
return udivmodsi4(a, b, 0);
}
long
__umodsi3(long a, long b)
{
return udivmodsi4(a, b, 1);
}