#include "libc.h"
#define LLSC_CLOBBERS "r0", "t", "memory"
#define LLSC_START(mem) \
"0: movli.l @" mem ", r0\n"
#define LLSC_END(mem) \
"1: movco.l r0, @" mem "\n" \
" bf 0b\n" \
" synco\n"
/* gusa is a hack in the kernel which lets you create a sequence of instructions
* which will be restarted if the process is preempted in the middle of the
* sequence. It will do for implementing atomics on non-smp systems. ABI is:
* r0 = address of first instruction after the atomic sequence
* r1 = original stack pointer
* r15 = -1 * length of atomic sequence in bytes
*/
#define GUSA_CLOBBERS "r0", "r1", "memory"
#define GUSA_START(mem,old,nop) \
" .align 2\n" \
" mova 1f, r0\n" \
nop \
" mov r15, r1\n" \
" mov #(0f-1f), r15\n" \
"0: mov.l @" mem ", " old "\n"
/* the target of mova must be 4 byte aligned, so we may need a nop */
#define GUSA_START_ODD(mem,old) GUSA_START(mem,old,"")
#define GUSA_START_EVEN(mem,old) GUSA_START(mem,old,"\tnop\n")
#define GUSA_END(mem,new) \
" mov.l " new ", @" mem "\n" \
"1: mov r1, r15\n"
#define CPU_HAS_LLSC 0x0040
int __sh_cas(volatile int *p, int t, int s)
{
int old;
if (__hwcap & CPU_HAS_LLSC) {
__asm__ __volatile__(
LLSC_START("%1")
" mov r0, %0\n"
" cmp/eq %0, %2\n"
" bf 1f\n"
" mov %3, r0\n"
LLSC_END("%1")
: "=&r"(old) : "r"(p), "r"(t), "r"(s) : LLSC_CLOBBERS);
} else {
__asm__ __volatile__(
GUSA_START_EVEN("%1", "%0")
" cmp/eq %0, %2\n"
" bf 1f\n"
GUSA_END("%1", "%3")
: "=&r"(old) : "r"(p), "r"(t), "r"(s) : GUSA_CLOBBERS, "t");
}
return old;
}
int __sh_swap(volatile int *x, int v)
{
int old;
if (__hwcap & CPU_HAS_LLSC) {
__asm__ __volatile__(
LLSC_START("%1")
" mov r0, %0\n"
" mov %2, r0\n"
LLSC_END("%1")
: "=&r"(old) : "r"(x), "r"(v) : LLSC_CLOBBERS);
} else {
__asm__ __volatile__(
GUSA_START_EVEN("%1", "%0")
GUSA_END("%1", "%2")
: "=&r"(old) : "r"(x), "r"(v) : GUSA_CLOBBERS);
}
return old;
}
int __sh_fetch_add(volatile int *x, int v)
{
int old, dummy;
if (__hwcap & CPU_HAS_LLSC) {
__asm__ __volatile__(
LLSC_START("%1")
" mov r0, %0\n"
" add %2, r0\n"
LLSC_END("%1")
: "=&r"(old) : "r"(x), "r"(v) : LLSC_CLOBBERS);
} else {
__asm__ __volatile__(
GUSA_START_EVEN("%2", "%0")
" mov %0, %1\n"
" add %3, %1\n"
GUSA_END("%2", "%1")
: "=&r"(old), "=&r"(dummy) : "r"(x), "r"(v) : GUSA_CLOBBERS);
}
return old;
}
void __sh_store(volatile int *p, int x)
{
if (__hwcap & CPU_HAS_LLSC) {
__asm__ __volatile__(
" mov.l %1, @%0\n"
" synco\n"
: : "r"(p), "r"(x) : "memory");
} else {
__asm__ __volatile__(
" mov.l %1, @%0\n"
: : "r"(p), "r"(x) : "memory");
}
}
void __sh_and(volatile int *x, int v)
{
int dummy;
if (__hwcap & CPU_HAS_LLSC) {
__asm__ __volatile__(
LLSC_START("%0")
" and %1, r0\n"
LLSC_END("%0")
: : "r"(x), "r"(v) : LLSC_CLOBBERS);
} else {
__asm__ __volatile__(
GUSA_START_ODD("%1", "%0")
" and %2, %0\n"
GUSA_END("%1", "%0")
: "=&r"(dummy) : "r"(x), "r"(v) : GUSA_CLOBBERS);
}
}
void __sh_or(volatile int *x, int v)
{
int dummy;
if (__hwcap & CPU_HAS_LLSC) {
__asm__ __volatile__(
LLSC_START("%0")
" or %1, r0\n"
LLSC_END("%0")
: : "r"(x), "r"(v) : LLSC_CLOBBERS);
} else {
__asm__ __volatile__(
GUSA_START_ODD("%1", "%0")
" or %2, %0\n"
GUSA_END("%1", "%0")
: "=&r"(dummy) : "r"(x), "r"(v) : GUSA_CLOBBERS);
}
}
