optromloader.asm: Comment on why ES needs to be initialized to zero.

rvalles · Oct 5, 2021 · aaaddb1 · aaaddb1
1 parent f7cf97c
commit aaaddb1
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/optromloader.asm b/optromloader.asm
@@ -29,7 +29,7 @@ start:
 	mov sp,$7C00 ;set a stack right under the bootloader
 	sti ;re-enable interrupts from 8086/86 workaround
 	mov ds,ax ;DS can't be trusted either
-	mov es,ax ;ES isn't any more trustworthy
+	mov es,ax ;ES isn't any more trustworthy, and is used by readblock below
 	mov si,banner_str
 	call printstr
 	;*** Load first block of ROM image (containing ROM header)