Initial commit

1 files changed, 54 insertions, 0 deletions

diff --git a/sys/etc/intr.x b/sys/etc/intr.x
new file mode 100644
index 00000000..e30d610c
--- /dev/null
+++ b/sys/etc/intr.x
@@ -0,0 +1,54 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<xwhen.h>
+
+define	LEN_SAVE	10
+
+# INTR_DISABLE, INTR_ENABLE -- Disable interrupts to protect a critical
+# section of code.  The interrupt handler is saved on a stack and restored
+# when interupts are reenabled.
+
+procedure intr_disable()
+
+int	sp
+int	save[LEN_SAVE]
+common	/zintde/ sp, save
+
+begin
+	sp = sp + 1
+	if (sp > LEN_SAVE)
+	    call sys_panic (1, "interrupt save stack overflow")
+
+	call zxwhen (X_INT, X_IGNORE, save[sp])
+end
+
+
+# INTR_ENABLE -- Reenable interrupts (restore saved interrupt handler).
+
+procedure intr_enable()
+
+int	junk
+int	sp
+int	save[LEN_SAVE]
+common	/zintde/ sp, save
+
+begin
+	if (sp <= 0)
+	    call sys_panic (1, "interrupt save stack underflow")
+
+	call zxwhen (X_INT, save[sp], junk)
+	sp = sp - 1
+end
+
+
+# INTR_RESET -- Clear the interrupt handler save stack.
+
+procedure intr_reset()
+
+int	sp
+int	save[LEN_SAVE]
+common	/zintde/ sp, save
+
+begin
+	sp = 0
+end