From b858cdf0393226cc18c3697679e2a1b6e8627778 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sun, 23 Jun 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-06-23

---
 pc/l.s | 42 ++++++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/pc/l.s b/pc/l.s
index 35240ca3737baf8c687d59d221adf38b0e45eff6..8001b317ea25e9d33dab3d3d1d912125319f6102 100644
--- a/pc/l.s
+++ b/pc/l.s
@@ -9,54 +9,53 @@ TEXT	start(SB),$0
 	/* never returns */
 
 /*
- *  standard traps
+ *  first 16 ``standard'' traps
  */
-
 TEXT	trap0(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$0
 	JMP	alltrap
 
 TEXT	trap1(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$1
 	JMP	alltrap
 
 TEXT	trap2(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$2
 	JMP	alltrap
 
 TEXT	trap3(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$3
 	JMP	alltrap
 
 TEXT	trap4(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$4
 	JMP	alltrap
 
 TEXT	trap5(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$5
 	JMP	alltrap
 
 TEXT	trap6(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$6
 	JMP	alltrap
 
 TEXT	trap7(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$7
 	JMP	alltrap
 
@@ -67,13 +66,13 @@ TEXT	trap8(SB),$0
 
 TEXT	trap9(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$9
 	JMP	alltrap
 
 TEXT	trap10(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$10
 	JMP	alltrap
 
@@ -99,22 +98,37 @@ TEXT	trap14(SB),$0
 
 TEXT	trap15(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$15
 	JMP	alltrap
 
+/*
+ *  invalid trap
+ */
 TEXT	invtrap(SB),$0
 
-	PUSHL	$0
+	PUSHL	$0	/* put on an error code */
 	PUSHL	$16
 	JMP	alltrap
 
+/*
+ *  common trap code
+ */
 alltrap:
+
 	PUSHAL
 	CALL	trap(SB)
 	POPAL
+	ADDL	$#8,SP		/* pop the trap and error codes */
 	IRETL
 
+/*
+ *  stubs
+ */
 TEXT	main(SB),$0
 
 	RET
+
+TEXT	trap(SB),$0
+
+	RET