From d70830b525684718cd2b8861b95bf9d6bfa3e21f Mon Sep 17 00:00:00 2001
From: emmanuel-marty <brothers@puzzlebrothers.com>
Date: Sat, 11 May 2019 11:42:00 +0200
Subject: [PATCH] Simplify nibble handling in LZSA2 8088 depacker

---
 asm/8088/decompress_small_v2.S | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/asm/8088/decompress_small_v2.S b/asm/8088/decompress_small_v2.S
index 61e99f7..1c2e65d 100755
--- a/asm/8088/decompress_small_v2.S
+++ b/asm/8088/decompress_small_v2.S
@@ -35,7 +35,7 @@ lzsa2_decompress:
    cld                     ; make string operations (lods, movs, stos..) move forward
 
    xor cx,cx
-   xor bx,bx
+   mov bx,0100H
    xor bp,bp
 
 .decode_token:
@@ -157,14 +157,12 @@ lzsa2_decompress:
    ret                     ; done
 
 .get_nibble:
-   dec bh                  ; nibble ready?
+   neg bh                  ; nibble ready?
    jns .has_nibble
    
-   mov cx,ax
+   xchg bx,ax
    lodsb                   ; load two nibbles
-   mov bl,al
-   mov bh,1
-   mov ax,cx
+   xchg ax,bx
 
 .has_nibble:
    mov cl,4                ; swap 4 high and low bits of nibble