From 501ede9be4bb6a1b1924f9acb3d771e24d6cd44c Mon Sep 17 00:00:00 2001
From: "Guillermo J. Rozas" <edu/mit/csail/zurich/gjr>
Date: Wed, 30 Sep 1992 03:55:47 +0000
Subject: [PATCH] Improve the real-mode keyboard interrupt handler to eliminate
 some jumps.

---
 v7/src/microcode/doskbutl.asm | 31 +++++++++----------------------
 1 file changed, 9 insertions(+), 22 deletions(-)

diff --git a/v7/src/microcode/doskbutl.asm b/v7/src/microcode/doskbutl.asm
index 5c066a96f..c527911a6 100644
--- a/v7/src/microcode/doskbutl.asm
+++ b/v7/src/microcode/doskbutl.asm
@@ -1,6 +1,6 @@
 ;;; -*-Midas-*-
 ;;;
-;;;	$Id: doskbutl.asm,v 1.5 1992/09/06 16:24:10 jinx Exp $
+;;;	$Id: doskbutl.asm,v 1.6 1992/09/30 03:55:47 jinx Exp $
 ;;;
 ;;;	Copyright (c) 1992 Massachusetts Institute of Technology
 ;;;
@@ -168,33 +168,20 @@ kbd_isr:
 	push	bx
 	and	bx,3fh			; Drop fncn
 
+	push	si
+	mov	si,word ptr cs:shifted_table_offset
 	test	al,7h			; Ctrl or shift set?
-	jne	do_shifted
+	jne	do_fetch
+
+	mov	si,word ptr cs:caps_table_offset
 	test	al,40h			; CAPS set?
-	jne	do_caps
+	jne	do_fetch
 
-do_unshifted:
-	push	si
 	mov	si,word ptr cs:unshifted_table_offset
-	mov	bl,byte ptr cs:[bx+si]
-	pop	si
-	jmp	merge
 
-do_shifted:
-	push	si
-	mov	si,word ptr cs:shifted_table_offset
-	mov	bl,byte ptr cs:[bx+si]
-	pop	si
-	jmp	merge
-
-do_caps:
-	push	si
-	mov	si,word ptr cs:caps_table_offset
-	mov	bl,byte ptr cs:[bx+si]
+do_fetch:
+	mov	bl,byte ptr cs:[bx+si]	; Fetch translated byte.
 	pop	si
-;	jmp	merge
-
-merge:
 	cmp	bl,0			; No translation?
 	je	abort_translation
 	; bt	al,2h			; Control set?
-- 
2.25.1