From 582645e269ee82d544ab8b8b913c8364f3178484 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Sun, 25 Jan 2009 17:23:32 -0800
Subject: [PATCH] Reorganize the codepage handling to allow ucs2 -> codepage
 conversion

Reorganize the codepage handling to make it easier to do ucs2 ->
codepage conversion, this will be used for a future directory lister.
---
 codepage/cptable.pl |  5 ++++-
 core/ldlinux.asm    | 28 +++++++++++++++++++++++++---
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/codepage/cptable.pl b/codepage/cptable.pl
index c7e2002..05cfc3e 100755
--- a/codepage/cptable.pl
+++ b/codepage/cptable.pl
@@ -118,6 +118,7 @@ for ($i = 0; $i < 256; $i++) {
 # Unicode (longname) matching table.
 # This only depends on the console codepage.
 #
+$pp0 = '';  $pp1 = '';
 for ($i = 0; $i < 256; $i++) {
     if (!defined($ytab[$i])) {
 	$p0 = $p1 = 0xffff;
@@ -136,8 +137,10 @@ for ($i = 0; $i < 256; $i++) {
     # Only the BMP is supported...
     $p0 = 0xffff if ($p0 > 0xffff);
     $p1 = 0xffff if ($p1 > 0xffff);
-    print CPOUT pack("vv", $p0, $p1);
+    $pp0 .= pack("v", $p0);
+    $pp1 .= pack("v", $p1);
 }
+print CPOUT $pp0, $pp1;
 close (CPOUT);
 
     
diff --git a/core/ldlinux.asm b/core/ldlinux.asm
index c7f6577..e9d0573 100644
--- a/core/ldlinux.asm
+++ b/core/ldlinux.asm
@@ -100,7 +100,8 @@ file_left	resd 1			; Number of sectors left
 .magic		resd 2			; 8-byte magic number
 .reserved	resd 6			; Reserved for future use
 .uppercase	resb 256		; Internal upper-case table
-.unicode	resw 2*256		; Unicode matching table
+.unicode	resw 256		; Unicode matching table
+.unicode_alt	resw 256		; Alternate Unicode matching table
 		endstruc
 
 %ifndef DEPEND
@@ -1040,10 +1041,10 @@ search_dos_dir:
 		cmp bx,[NameLen]
 		jae .vfat_tail
 		movzx bx,byte [bx+di]
-		shl bx,2
+		add bx,bx
 		cmp ax,[cp_unicode+bx]		; Primary case
 		je .ucs_ok
-		cmp ax,[cp_unicode+bx+2]	; Alternate case
+		cmp ax,[cp_unicode_alt+bx]	; Alternate case
 		je .ucs_ok
 		; Mismatch...
 		jmp .not_us_pop
@@ -1170,8 +1171,29 @@ codepage	equ $-(32+32)
 codepage_data:	incbin "codepage.cp",32+32
 cp_uppercase	equ	codepage+cp.uppercase
 cp_unicode	equ	codepage+cp.unicode
+cp_unicode_alt	equ	codepage+cp.unicode_alt
 codepage_end	equ $
 
+		section .text
+;
+; Input:  UCS-2 character in AX
+; Output: Single byte character in AL, ZF = 1
+;         On failure, returns ZF = 0
+;
+; Assumes CS == ES == 0.
+;
+ucs2_to_cp:
+		push di
+		push cx
+		mov di,cp_unicode
+		mov cx,512
+		repne scasw
+		xchg ax,cx
+		pop cx
+		pop di
+		not ax		; Doesn't change the flags!
+		ret
+
 		section .bss
 VFATInit	resb 1
 VFATNext	resb 1
-- 
2.7.4