Macroize the 2048-byte sector size.

diff --git a/isolinux.asm b/isolinux.asm
index f000506..eb64a32 100644 (file)
--- a/isolinux.asm
+++ b/isolinux.asm
@@ -35,6 +35,8 @@ DEFAULT_BAUD  equ 9600                ; Default baud rate for serial port
 BAUD_DIVISOR   equ 115200              ; Serial port parameter
 MAX_OPEN_LG2   equ 6                   ; log2(Max number of open files)
 MAX_OPEN       equ (1 << MAX_OPEN_LG2)
+SECTORSIZE_LG2 equ 11                  ; 2048 bytes/sector (El Torito requirement)
+SECTORSIZE     equ (1 << SECTORSIZE_LG2)
 
 ;
 ; Should be updated with every release to avoid bootsector/SYS file mismatch
@@ -375,7 +377,7 @@ _start1:    xor ax,ax
                ;
 initial_csum:  xor edi,edi
                mov si,_start1
-               mov cx,(2048-64) >> 2
+               mov cx,(SECTORSIZE-64) >> 2
 .loop:         lodsd
                add edi,eax
                loop .loop
@@ -383,7 +385,7 @@ initial_csum:       xor edi,edi
 
                ; Set up boot file sizes
                mov eax,[bi_length]
-               sub eax,2048-3
+               sub eax,SECTORSIZE-3
                shr eax,2                       ; bytes->dwords
                mov [ImageDwords],eax           ; boot file dwords
                add eax,(2047 >> 2)
@@ -638,7 +640,7 @@ getlinsec_cdrom:
                movzx eax,word [si+2]           ; Sectors we read
                add [si+8],eax                  ; Advance sector pointer
                sub bp,ax                       ; Sectors left
-               shl ax,11-4                     ; 2048-byte sectors -> segment
+               shl ax,SECTORSIZE_LG2-4         ; 2048-byte sectors -> segment
                add [si+6],ax                   ; Advance buffer pointer
                and bp,bp
                jnz .loop