diff options
| -rw-r--r-- | mos/sys/arch/x86_64/cpu/prim.S | 5 | ||||
| -rw-r--r-- | mos/sys/inc/mu/cpu.h | 11 |
2 files changed, 16 insertions, 0 deletions
diff --git a/mos/sys/arch/x86_64/cpu/prim.S b/mos/sys/arch/x86_64/cpu/prim.S index 6f82153..707eb86 100644 --- a/mos/sys/arch/x86_64/cpu/prim.S +++ b/mos/sys/arch/x86_64/cpu/prim.S @@ -7,6 +7,7 @@ .globl mu_cpu_halt .globl mu_irq_state .globl mu_irq_setmask + .globl mu_cpu_aswap mu_cpu_halt: hlt retq @@ -19,6 +20,10 @@ mu_irq_state: shr $9, %rax /* IF */ and $1, %rax /* Isolate */ retq +mu_cpu_aswap: + xchg %rsi, (%rdi) /* Swap */ + mov %rsi, %rax /* Return old value */ + retq mu_irq_setmask: test $1, %rdi jnz irq_mask diff --git a/mos/sys/inc/mu/cpu.h b/mos/sys/inc/mu/cpu.h index e91a084..9856df8 100644 --- a/mos/sys/inc/mu/cpu.h +++ b/mos/sys/inc/mu/cpu.h @@ -23,6 +23,17 @@ BOOL mu_irq_state(void); void mu_irq_setmask(BOOL mask); /* + * Perform an atomic swap operation + * + * @p: Memory area to store `val' to + * @val: Value to write to `p' + * + * Returns the value at `p' before `val' was + * written + */ +USIZE mu_cpu_aswap(USIZE *p, USIZE val); + +/* * Halt the current processor core */ void mu_cpu_halt(void); |