diff options
Diffstat (limited to 'memdisk/memdisk.asm')
| -rw-r--r-- | memdisk/memdisk.asm | 51 |
1 files changed, 11 insertions, 40 deletions
diff --git a/memdisk/memdisk.asm b/memdisk/memdisk.asm index 610af31d..11234501 100644 --- a/memdisk/memdisk.asm +++ b/memdisk/memdisk.asm @@ -17,7 +17,7 @@ ; ; **************************************************************************** -%define DEBUG_TRACERS ; Uncomment to get debugging tracers +; %define DEBUG_TRACERS ; Uncomment to get debugging tracers %ifdef DEBUG_TRACERS @@ -80,8 +80,6 @@ Int13Start: pop dx js .nomatch ; If SF=0, we have a class match here jz .our_drive ; If ZF=1, we have an exact match - cmp ah,08h ; Is it Get Drive Parameters? - je .our_drive ; If so always handle for our own class cmp dl,[cs:DriveNo] jb .nomatch ; Drive < Our drive dec dl ; Drive > Our drive, adjust drive # @@ -116,7 +114,10 @@ Done: ; Standard routine for return mov P_AX,ax DoneWeird: TRACER 'D' - mov [LastStatus],ah + xor bx,bx + mov es,bx + mov bx,[StatusPtr] + mov [es:bx],ah ; Save status and ah,ah lds ebx,[Stack] @@ -133,7 +134,6 @@ DoneWeird: Reset: ; Reset affects multiple drives, so we need to pass it on TRACER 'R' - mov [LastStatus],al ; Clear the status (AL = 0) pop ax ; Drop return address popad ; Restore all registers pop es @@ -168,7 +168,10 @@ GetDriveType: jmp short DoneWeird ; But don't stick it into P_AX GetStatus: - mov ah,[LastStatus] ; Copy last status + xor ax,ax + mov es,ax + mov bx,[StatusPtr] + mov ah,[bx] ; Copy last status ret Read: @@ -201,14 +204,7 @@ success: ret GetParms: - ; This gets invoked even for other drives, so that - ; we can modify the drive count on return TRACER 'G' - mov dx,P_DX ; The drive whose number we're stealing - cmp dl,[DriveNo] - jb .belowdrive - ja .abovedrive - TRACER 'M' mov dl,[DriveCnt] ; Cached data mov P_DL,dl test byte [DriveNo],80h @@ -232,31 +228,6 @@ GetParms: xor ax,ax ret - ; If another disk, just mangle DL on return -.abovedrive: - TRACER 'A' - dec dl ; Adjust drive # to what the BIOS believes -.belowdrive: - TRACER 'B' - mov di,P_DI - mov ax,P_ES - mov es,ax - mov bx,P_BX - mov cx,P_CX - mov ax,P_AX - pushf - call far [OldInt13] - inc dl ; Add ourselves to the count - mov P_AX,ax - mov P_BX,bx - mov P_CX,cx - mov P_DX,dx - mov P_DI,di - mov cx,es - mov P_ES,cx - TRACER 'R' - ret - ; Set up registers as for a "Read", and compares against disk size setup_regs: @@ -509,6 +480,7 @@ DriveNo db 0 ; Our drive number DriveType db 0 ; Our drive type (floppies) DriveCnt db 0 ; Drive count (from the BIOS) db 0 ; Pad + BPT dd 0 ; BIOS parameter table pointer (floppies) MyStack dw 0 ; Offset of stack @@ -518,8 +490,7 @@ MyStack dw 0 ; Offset of stack Stack dd 0 ; Saved SS:ESP on invocation dw 0 SavedAX dw 0 ; AX saved on invocation - -LastStatus db 0 ; Last return status +StatusPtr dw 0 ; Where to save status (zeroseg ptr) alignb 4, db 0 ; We *MUST* end on a dword boundary |