I'd like to hear the behavior of 0x7e00 that may differ in other sectors.
All I know is that address is indicating the final byte for the sector 1 (the code I provided is for demonstration)
org 0x7c00
bits 16
; CHS configuration
mov ah, 0x02
mov al, 1
mov ch, 0
mov cl, 2
mov dl, 0x00 ; I don't know if that's correct register, I forgot
mov es, [zero]
mov bx, 0x7e00 ; supposedly [es:bx]
int 13h
zero:
db 0
times 510 - ($-$$) db 0
dw 0x55AA
times 0x400 - ($-$$) db 0
Either it may use the same address as I already configured the CHS values in the top of the code (after org & bits instruction), or...
mov cl, 3 ; Sector number
mov bx, 0x7e00? 0xfc00?
If not, then I could multiply the hexadecimal value by 2 as I'm two sectors ahead (or by more if way further) from the boot one.