mos/x86_64: Add processor primitives + MU interface

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 64 insertions, 0 deletions

diff --git a/mos/sys/arch/x86_64/cpu/prim.S b/mos/sys/arch/x86_64/cpu/prim.S
new file mode 100644
index 0000000..7ab6269
--- /dev/null
+++ b/mos/sys/arch/x86_64/cpu/prim.S
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2025, Ian Moffett.
+ * Provided under the BSD-3 clause.
+ */
+
+    .globl mu_cpu_halt
+    .globl mu_irq_state
+    .globl mu_irq_setmask
+mu_cpu_halt:
+    hlt
+    retq
+mu_cpu_pause:
+    pause
+    retq
+mu_irq_state:
+    pushfq
+    pop %rax
+    shr $9, %rax        /* IF */
+    and $1, %rax        /* Isolate */
+    retq
+mu_irq_setmask:
+    test $1, %rdi
+    jnz irq_mask
+    sti
+    retq
+irq_mask:
+    cli
+    retq
diff --git a/mos/sys/inc/mu/cpu.h b/mos/sys/inc/mu/cpu.h
new file mode 100644
index 0000000..e91a084
--- /dev/null
+++ b/mos/sys/inc/mu/cpu.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2025, Ian Moffett.
+ * Provided under the BSD-3 clause.
+ */
+
+#ifndef _MU_CPU_H_
+#define _MU_CPU_H_ 1
+
+#include <sdk/types.h>
+
+/*
+ * Get the current IRQ state
+ *
+ * (TRUE: IRQs unmasked, FALSE: IRQs masked)
+ */
+BOOL mu_irq_state(void);
+
+/*
+ * Mask or unmask IRQs
+ *
+ * @mask: If true, mask IRQs
+ */
+void mu_irq_setmask(BOOL mask);
+
+/*
+ * Halt the current processor core
+ */
+void mu_cpu_halt(void);
+
+/*
+ * Signal a spinwait hint to the currnet
+ * processor core
+ */
+void mu_cpu_pause(void);
+
+#endif  /* !_MU_CPU_H_ */