optromloader.asm, Makefile: Make BIOS drive a parameter.

rvalles · Sep 24, 2021 · e58cbf7 · e58cbf7
1 parent f8129f1
commit e58cbf7
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Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/Makefile b/Makefile
@@ -1,5 +1,5 @@
 fasm = fasm
-fasm_extraopts =
+fasm_extraopts = -d bios_drive=0
 #fasm_extraopts += -d target_segment=0xE000
 readblock_retries = 7
 hexdumpcmd = hexdump -C

diff --git a/optromloader.asm b/optromloader.asm
@@ -202,7 +202,7 @@ readblock: ;AX blockno, [ES:BX] dest, trashes AX (reserved, retval)
 	mov cl,ah ;CHS sector in LSB, cyl MSB (zero) in MSB
 	mov ah,02h ;BIOS 13h read CHS block
 	mov al,1 ;sectors to read 1..128
-	mov dl,0 ;drive 0=A 80h=hdd0
+	mov dl,bios_drive ;drive 0=A 80h=hdd0
 	mov di,readblock_tries ;how many read attempts before giving up
 .retry:
 	push ax ;preserve AX for potential retries
@@ -220,7 +220,7 @@ readblock: ;AX blockno, [ES:BX] dest, trashes AX (reserved, retval)
 	mov al,ah ;status was returned in AH
 	call printhex8 ;status value
 	mov ah,0 ;reset command
-	mov dl,0 ;drive 0=A 80h=hdd0
+	mov dl,bios_drive ;drive 0=A 80h=hdd0
 	int 13h ;call BIOS function for disk operations
 	mov si,readblocks_str
 	call printstr ;reprint header in next line to preserve read error on screen