diff options
Diffstat (limited to 'arch/sh/src/atomic.c')
| -rw-r--r-- | arch/sh/src/atomic.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/arch/sh/src/atomic.c b/arch/sh/src/atomic.c new file mode 100644 index 00000000..d29b0538 --- /dev/null +++ b/arch/sh/src/atomic.c @@ -0,0 +1,146 @@ +#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); + } +} |