OSDev.org

Code: Select all

push 0 ;first we push the last argument: the LBA sector to be written to.
push 0 ;then the base address of what we want to write
push eax ;then the Service ID of the base. A service is roughly the same as a segment to be selected in any segment register.
push 0x0004000c ;this is the callcode, specifying what we want the kernel to do. When CC=0x0004000c, it knows we want to do fdwrsec
int 0x30 ;this will call the kernel, and return an errorcode in eax.
add esp, 4*4 ;cleaning up the stack

Code: Select all

cc0004000c:;fdwrsec(cc, basesid, base, sector), eax=ec
;Writes one sector to floppy disk.
	
	;Get CHS
	push 3
	call getarg;eax=?sector (getarg is a local function, returning argn in eax)
	add esp, 4*1
	
	push eax;sec
	push 0x00040000;cc=getchs
	int 0x30;eax=c, ebx=h, ecx=s
	add esp, 4*2
	
	mov edx, eax;edx=c (to free eax of the burden of storage)
	
	;Issue command 0xC5
	push 0xc5;command
	push 0x00040001;cc=fdcommand
	int 0x30;eax=ec
	add esp, 4*2
	
	mov rs_eax, eax;ec
	test eax, eax
	jnz .ret
	
	;parameter 1: h*4+drive
	shl ebx, 2
	
	push ebx
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	shr ebx, 2
	
	;parameter 2: c
	push edx;parameter
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	;parameter 3: h
	push ebx;parameter
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	;parameter 4: s
	push ecx;parameter
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	;parameter 5: 2
	push 2;parameter
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	;parameter 6: sector count (1)
	push 1;parameter
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	;parameter 7: 0x1b
	push 0x1b;parameter
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	;parameter 8: 0xff
	push 0xff;parameter
	push 0x00040002;cc=fdparameter
	int 0x30
	add esp, 4*2
	
	;Transfer data
	push 2
	call getarg;eax=?base
	add esp, 4*1
	mov ebx, eax;ebx=?base
	
	push 1
	call getarg;eax=?basesid
	add esp, 4*1
	
	push ebx;base
	push eax;basesid
	push 0x00040004;cc=fdo (Another critical system call. This will output 512 bytes to the FIFO. Code below this.)
	int 0x30;eax=ec
	add esp, 4*3
	
	mov rs_eax, eax;ec
	test eax, eax
	jnz .ret
	
	;result 1: st0
	push 0x00040005;cc=fdresult
	int 0x30;eax=result
	add esp, 4*1
	
	;result 2: st1
	push 0x00040005;cc=fdresult
	int 0x30;eax=result
	add esp, 4*1
	mov ebx, eax;ebx=st1
	
	;result 3: st2
	push 0x00040005;cc=fdresult
	int 0x30;eax=result
	add esp, 4*1
	
	;result 4: c
	push 0x00040005;cc=fdresult
	int 0x30;eax=result
	add esp, 4*1
	
	;result 5: h
	push 0x00040005;cc=fdresult
	int 0x30;eax=result
	add esp, 4*1
	
	;result 6: s
	push 0x00040005;cc=fdresult
	int 0x30;eax=result
	add esp, 4*1
	
	;result 7: 2
	push 0x00040005;cc=fdresult
	int 0x30;eax=result
	add esp, 4*1
	
	;Check st1	
	mov rs_eax, 0x00040001
	test bl, 00010000b
	jnz .ret
	
	mov rs_eax, 0x00040002
	test bl, 00000010b
	jnz .ret
	
	mov rs_eax, 0;ec
	
	.ret:
	ret

Code: Select all

cc00040004:;fdo(cc, basesid, base), eax=ec
;Send data from base to FDC.
	
	push 1
	call getarg;eax=?basesid
	add esp, 4*1
	
	push eax;sid
	push 0x00020019;cc=sidds
	int 0x30;eax=ec, ds=segment (You just have to trust some functions. Including this one. This will load our base segment into ds)
	add esp, 4*2
	
	mov rs_eax, eax;ec
	test eax, eax
	jnz .ret
	
	push 2
	call getarg;eax=?base
	add esp, 4*1
	mov ebx, eax;ebx=?base
	
	mov ecx, 512;counter
	
	@@:
		
		mov dx, 0x03f4;select MSR
		in al, dx;get MSR
		
		test al, 00100000b;test NDMA
		jz @b;Jump if data not ready
		
		test al, 10000000b;test RQM
		jz @b;jump if data not ready
		
		mov dx, 0x03f5;select FIFO
		mov al, [ebx];get data
		out dx, al;set data
		
		inc ebx;update pointer
		dec ecx;update counter
		jnz @b
	
	mov rs_eax, 0;ec
	
	.ret:
	ret

Code: Select all

[BIOS] Booting from 0000:7c00
[FLOPPY] controller reset in software (This tells me that my floppy driver is starting its initialization) 
[FLOPPY] controller reset in software (This tells me that my floppy driver is specifying)
[FLOPPY] non DMA mode not fully implemented yet

Code: Select all

call getarg;eax=?base