Implement syscall interface and version data
This commit is contained in:
parent
576b2c6546
commit
f7d7f48026
145
src/@rdos.asm
145
src/@rdos.asm
|
|
@ -1,6 +1,21 @@
|
|||
org 0x700
|
||||
cseg equ 0x0
|
||||
jmp init
|
||||
|
||||
%include "version.inc"
|
||||
|
||||
jmp _entry
|
||||
banner db "RDOS KERNEL 1.0", 0x0A, 0x0D, '$', 0x1A
|
||||
_entry call .l01
|
||||
.l01 pop ax
|
||||
sub ax, .l01
|
||||
mov cl, 4
|
||||
shr ax, cl
|
||||
mov cx, cs
|
||||
add cx, ax
|
||||
push cx
|
||||
mov ax, start
|
||||
push ax
|
||||
retf
|
||||
|
||||
;;; Character I/O
|
||||
|
||||
|
|
@ -138,10 +153,15 @@ gets mov si, dx
|
|||
call putc
|
||||
ret
|
||||
|
||||
;;; System functions
|
||||
|
||||
; Return OS version from version.inc
|
||||
ver mov bx, bdosver | 0x1000
|
||||
ret
|
||||
|
||||
;;; Disk i/o
|
||||
|
||||
%include "bpb.inc"
|
||||
%include "farptr.inc"
|
||||
|
||||
; dflags bitfields
|
||||
DRVLOG equ 0x01 ; bit 0 - drive logged in (see drvnum)
|
||||
|
|
@ -150,23 +170,8 @@ DRVEXT equ 0x04 ; bit 2 - EBIOS supported
|
|||
DIRTY equ 0x08 ; bit 3 - dskbuf dirty
|
||||
DRVCHS equ 0x10 ; bit 4 - CHS geometry known
|
||||
|
||||
align 16
|
||||
; IBM Interrupt Sharing Protocol structure
|
||||
i13isp jmp short int13i
|
||||
dw 0,0xFFFF
|
||||
dw 0x424B
|
||||
db 0
|
||||
iret
|
||||
align 16
|
||||
|
||||
; Entry point when user program calls int13h
|
||||
; TODO: flush buffer and log out drive
|
||||
int13i call int13
|
||||
iret
|
||||
|
||||
; Wrapper around int 13h
|
||||
int13 pushf
|
||||
call far [i13isp+2]
|
||||
int13 int 0x13
|
||||
; TODO: on error: reset & retry
|
||||
; TODO: record errors
|
||||
; TODO: multi-track reading
|
||||
|
|
@ -209,10 +214,10 @@ getprm test byte [dflags], DRVEXT
|
|||
test ax, ax
|
||||
jz .ret
|
||||
; copy BIOS dpt table over ours
|
||||
mov dx, dpt
|
||||
mov bx, di
|
||||
mov cx, 11
|
||||
call lodfar
|
||||
;mov dx, dpt
|
||||
;mov bx, di
|
||||
;mov cx, 11
|
||||
;call lodfar
|
||||
.ret ret
|
||||
|
||||
; select a drive for io
|
||||
|
|
@ -379,14 +384,13 @@ flush test word [cs:dflags], DIRTY
|
|||
; Sector number is read from [drvseek]
|
||||
diskio mov cl, 1 ; read len
|
||||
; DS := ES := CS
|
||||
call rstseg
|
||||
mov ds, [cs:dseg]
|
||||
; check if ebios supported
|
||||
test word [dflags], DRVEXT
|
||||
jz .noext
|
||||
; set up regs for ebios call
|
||||
mov ax, cx
|
||||
xchg ax, cx
|
||||
or ah, 0x40
|
||||
mov si, dap
|
||||
jmp .do
|
||||
; check if we can skip controller reset
|
||||
.noext test word [dflags], DRVCTL
|
||||
|
|
@ -419,15 +423,19 @@ diskio mov cl, 1 ; read len
|
|||
; shuffle values around for bios
|
||||
xchg ax, cx
|
||||
xchg dh, dl
|
||||
mov bx, dskbuf
|
||||
.do mov dl, [biosnum]
|
||||
; ah: subfunction selected via cx previously
|
||||
; al: 1 = reading 1 sector
|
||||
; cx: sector and cylinder number
|
||||
; dh: head number
|
||||
; dl: drive number
|
||||
; bx: offset to disk buffer
|
||||
push es
|
||||
push si
|
||||
mov si, dap
|
||||
les bx, [si+4]
|
||||
call int13
|
||||
pop si
|
||||
pop es
|
||||
jc .err
|
||||
; clear dirty flag on success
|
||||
and word [dflags], ~DIRTY
|
||||
|
|
@ -439,39 +447,6 @@ diskio mov cl, 1 ; read len
|
|||
stc
|
||||
ret
|
||||
|
||||
init mov ax, cs
|
||||
; boot failure if loaded wrong
|
||||
cmp ax, cseg
|
||||
je $+4
|
||||
int 0x18
|
||||
call rstseg
|
||||
; fetch current DPT
|
||||
les bx, [4*0x1E]
|
||||
mov dx, dpt
|
||||
mov cx, 11
|
||||
call lodfar
|
||||
; set interrupt vector
|
||||
mov word [4*0x1E], dpt
|
||||
mov word [4*0x1E+2], ds
|
||||
; save int 13 handler
|
||||
les bx, [4*0x13]
|
||||
mov [i13isp+2], bx
|
||||
mov [i13isp+4], es
|
||||
; install ours
|
||||
mov word [4*0x13], int13i
|
||||
mov [4*0x13+2], cs
|
||||
|
||||
; install int21h handler
|
||||
mov word [4*0x21], int21h
|
||||
mov [4*0x21+2], cs
|
||||
|
||||
mov dl, 0x36
|
||||
mov ah, 2
|
||||
int 0x21
|
||||
|
||||
halt hlt
|
||||
jmp halt
|
||||
|
||||
;;; Export functions as syscalls
|
||||
; SP, BP, SI, DI and ES must be preserved by kernel code
|
||||
; DL, DX or DS:DX is input argument from prog
|
||||
|
|
@ -494,7 +469,9 @@ intE0h push bx
|
|||
; bx = syscall number
|
||||
; stack must be -> BX IP CS FL
|
||||
; for return to prog
|
||||
sysc add bx, bx
|
||||
sysc sti
|
||||
cld
|
||||
add bx, bx
|
||||
mov bx, [cs:bx+stab]
|
||||
test bh, srw >> 8 ; fork off bx returns
|
||||
jnz .l02
|
||||
|
|
@ -537,6 +514,38 @@ sysc add bx, bx
|
|||
pop dx
|
||||
ret
|
||||
|
||||
start xor ax, ax
|
||||
mov ds, ax
|
||||
|
||||
; install int20h handler
|
||||
mov word [4*0x20], start
|
||||
mov [4*0x20+2], cs
|
||||
; install int21h handler
|
||||
mov word [4*0x21], int21h
|
||||
mov [4*0x21+2], cs
|
||||
; install intE0h handler
|
||||
mov word [4*0xE0], intE0h
|
||||
mov [4*0xE0+2], cs
|
||||
|
||||
mov ax, cs
|
||||
mov ds, ax
|
||||
mov [dseg], ax
|
||||
|
||||
; print banner
|
||||
mov dx, banner
|
||||
call puts
|
||||
|
||||
; read cmdline
|
||||
mov dl, '>'
|
||||
call putc
|
||||
mov dx, inbuf
|
||||
mov byte [inbuf], 72
|
||||
call gets
|
||||
|
||||
halt sti
|
||||
hlt
|
||||
jmp halt
|
||||
|
||||
section .rodata
|
||||
|
||||
; syscall table
|
||||
|
|
@ -549,10 +558,10 @@ stab dw 0 ; 0 reboot
|
|||
dw 0 ; 6 direct console i/o
|
||||
dw 0 ; 7 read i/o byte
|
||||
dw 0 ; 8 get i/o byte
|
||||
dw 0 ; 9 string output
|
||||
dw 0 ; 10 string input
|
||||
dw puts ; 9 string output
|
||||
dw gets ; 10 string input
|
||||
dw 0 ; 11 console status
|
||||
dw 0 ; 12 get version number
|
||||
dw ver ; 12 get version number
|
||||
dw 0 ; 13 reset disks
|
||||
dw 0 ; 14 set drive
|
||||
dw 0 ; 15 open file
|
||||
|
|
@ -587,7 +596,8 @@ section .data
|
|||
|
||||
dap db 0x10, 0
|
||||
dw 1
|
||||
dw dskbuf, cseg
|
||||
dw dskbuf
|
||||
dseg dw 0
|
||||
drvseek dw 0,0,0,0
|
||||
|
||||
; bit 0 (1) - drive logged in (see drvnum)
|
||||
|
|
@ -603,9 +613,6 @@ drvnum resb 1
|
|||
; number, just for bios
|
||||
biosnum resb 1
|
||||
|
||||
; DPT tables for 4 floppy drives
|
||||
dpt resb 4*14
|
||||
|
||||
; Information for logged in drive
|
||||
drvss resb 1 ; sector size, 2^(7+n) bytes
|
||||
drvcs resb 1 ; cluster size, 2^(7+n) bytes
|
||||
|
|
@ -622,3 +629,5 @@ drvfn resb 2 ; sectors per fat table
|
|||
; disk buffer for I/O operations
|
||||
alignb 2
|
||||
dskbuf resb 1024
|
||||
|
||||
inbuf resb 128
|
||||
|
|
|
|||
|
|
@ -1,46 +0,0 @@
|
|||
; reset segments
|
||||
rstseg mov ax, cs
|
||||
mov ds, ax
|
||||
mov es, ax
|
||||
ret
|
||||
|
||||
; copy to far memory
|
||||
; IN es:bx far memory ptr (preserved)
|
||||
; ds:dx local ptr (preserved)
|
||||
; cx number of bytes to transfer
|
||||
; OUT cx set to zero
|
||||
; si & di trashed
|
||||
stofar mov si, dx
|
||||
mov di, bx
|
||||
rep movsb
|
||||
ret
|
||||
|
||||
; copy from far memory
|
||||
; IN es:bx far memory ptr (preserved)
|
||||
; ds:dx local ptr (preserved)
|
||||
; cx number of bytes to copy
|
||||
; OUT cx set to zero
|
||||
; si & di trashed
|
||||
lodfar call swpds
|
||||
mov si, bx
|
||||
mov di, dx
|
||||
rep movsb
|
||||
|
||||
; exchange es and ds
|
||||
swpds push ds
|
||||
push es
|
||||
pop ds
|
||||
pop es
|
||||
ret
|
||||
|
||||
; normalize ptr in ds:dx
|
||||
norm mov ax, ds
|
||||
mov cl, 4
|
||||
push dx
|
||||
ror dx, cl
|
||||
and dh, 0xF
|
||||
add ax, dx
|
||||
mov ds, ax
|
||||
pop dx
|
||||
and dx, 0xF
|
||||
ret
|
||||
|
|
@ -0,0 +1,2 @@
|
|||
bdosver equ 0x10 ; CP/M 1.0
|
||||
bdosrev equ 0
|
||||
Loading…
Reference in New Issue