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Turn CHS fields in drive table into words 

CHS arithmetic will be done on 32-bit integers, the operand for division
of DX:AX is a word, so we save a conversion step.

Additionally, i might reuse these fields for pointing to a SYS driver later.
This commit is contained in:
Nero 2019-09-24 08:16:22 +00:00
parent cd7aafde09
commit 6411dc0c9c
1 changed files with 11 additions and 7 deletions
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18
kernel/drive.asm
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@ -1,11 +1,15 @@
; drive table
%define drivetab_type 0x00 ; BYTE 0=unassigned, 1=BIOS/CHS, 2=BIOS/LBA
%define drivetab_num 0x01 ; BYTE DL number
%define drivetab_heads 0x02 ; CHS heads
%define drivetab_spt 0x03 ; CHS sectors per track
%define drivetab_sectors 0x04 ; total number of sectors
%define drivetab_offset 0x08 ; partition offset
%define drivetab_size 0x0C
%define drivetab_type 0x00 ; BYTE 0=unassigned, 1=BIOS/CHS, 2=BIOS/LBA
%define drivetab_num 0x01 ; BYTE DL number
; CHS data for type=1
; Might be reused for driver address
%define drivetab_heads 0x02 ; WORD CHS heads
%define drivetab_spt 0x04 ; WORD CHS sectors per track
%define drivetab_sectors 0x06 ; DWORD total number of sectors
%define drivetab_offset 0x0A ; DWORD partition offset
%define drivetab_size 0x0E
drive_table:
dw 0