patch-2.1.80 linux/include/asm-arm/proc-armv/semaphore.h

• Lines: 82
• Date: Tue Jan 20 16:39:43 1998
• Orig file: v2.1.79/linux/include/asm-arm/proc-armv/semaphore.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.79/linux/include/asm-arm/proc-armv/semaphore.h linux/include/asm-arm/proc-armv/semaphore.h
@@ -0,0 +1,81 @@
+/*
+ * linux/include/asm-arm/semaphore.h
+ */
+#ifndef __ASM_PROC_SEMAPHORE_H
+#define __ASM_PROC_SEMAPHORE_H
+
+/*
+ * This is ugly, but we want the default case to fall through.
+ * "__down" is the actual routine that waits...
+ */
+extern inline void down(struct semaphore * sem)
+{
+	__asm__ __volatile__ ("
+	@ atomic down operation
+	mrs	r0, cpsr
+	orr	r1, r0, #128		@ disable IRQs
+	bic	r0, r0, #0x80000000	@ clear N
+	msr	cpsr, r1
+	ldr	r1, [%0]
+	subs	r1, r1, #1
+	str	r1, [%0]
+	orrmi	r0, r0, #0x80000000	@ set N
+	msr	cpsr, r0
+	movmi	r0, %0
+	blmi	" SYMBOL_NAME_STR(__down)
+		: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
+}
+
+/*
+ * This is ugly, but we want the default case to fall through.
+ * "__down_interruptible" is the actual routine that waits...
+ */
+extern inline int down_interruptible (struct semaphore * sem)
+{
+	int result;
+	__asm__ __volatile__ ("
+	@ atomic down operation
+	mrs	r0, cpsr
+	orr	r1, r0, #128		@ disable IRQs
+	bic	r0, r0, #0x80000000	@ clear N
+	msr	cpsr, r1
+	ldr	r1, [%1]
+	subs	r1, r1, #1
+	str	r1, [%1]
+	orrmi	r0, r0, #0x80000000	@ set N
+	msr	cpsr, r0
+	movmi	r0, %1
+	movpl	r0, #0
+	blmi	" SYMBOL_NAME_STR(__down_interruptible) "
+	mov	%0, r0"
+		: "=r" (result)
+		: "r" (sem)
+		: "r0", "r1", "r2", "r3", "ip", "lr", "cc");
+	return result;
+}
+
+/*
+ * Note! This is subtle. We jump to wake people up only if
+ * the semaphore was negative (== somebody was waiting on it).
+ * The default case (no contention) will result in NO
+ * jumps for both down() and up().
+ */
+extern inline void up(struct semaphore * sem)
+{
+	__asm__ __volatile__ ("
+	@ atomic up operation
+	mrs	r0, cpsr
+	orr	r1, r0, #128		@ disable IRQs
+	bic	r0, r0, #0x80000000	@ clear N
+	msr	cpsr, r1
+	ldr	r1, [%0]
+	adds	r1, r1, #1
+	str	r1, [%0]
+	orrls	r0, r0, #0x80000000	@ set N
+	msr	cpsr, r0
+	movmi	r0, %0
+	blmi	" SYMBOL_NAME_STR(__up)
+		: : "r" (sem) : "r0", "r1", "r2", "r3", "ip", "lr", "cc");
+}
+
+#endif