Changeset 258 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/FindDPT.asm

Timestamp:

Feb 22, 2012, 7:01:53 PM (12 years ago)

Author:

gregli@…

google:author:

gregli@hotmail.com

Message:

Added floppy drive emulation over the serial connection (MODULE_SERIAL_FLOPPY). Along the way, various optimizations were made to stay within the 8K ROM size target. Also, serial code now returns the number of sectors transferred.

File:

• trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/FindDPT.asm (modified) (6 diffs)

trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/FindDPT.asm

@@ -14 +14 @@
 ;       DS:DI:  Ptr to first unused DPT
 ;   Corrupts registers:
-;       DL
+;       DX
 ;--------------------------------------------------------------------
 ALIGN JUMP_ALIGN
 FindDPT_ForNewDriveToDSDI:
-    mov     dl, [RAMVARS.bFirstDrv]
-    add     dl, [RAMVARS.bDrvCnt]
+    mov     ax, [RAMVARS.wDrvCntAndFirst]
+    add     al, ah
+%ifdef MODULE_SERIAL_FLOPPY
+    add     al, [RAMVARS.xlateVars+XLATEVARS.bFlopCreateCnt]
+%endif
+    xchg    ax, dx      
     ; Fall to FindDPT_ForDriveNumber
 
@@ -41 +45 @@
     xchg    di, ax  ; Save the contents of AX in DI
 
+%ifdef MODULE_SERIAL_FLOPPY
+    mov     ax, [RAMVARS.wDrvCntAndFirst]
+        
+    test    dl, dl
+    js      .harddisk
+
+    call    RamVars_UnpackFlopCntAndFirstToAL
+    add     dl, ah                      ; add in end of hard disk DPT list, floppies start immediately after
+.harddisk:
+    sub     dl, al                      ; subtract off beginning of either hard disk or floppy list (as appropriate)
+%else
+    sub     dl, [RAMVARS.bFirstDrv]     ; subtract off beginning of hard disk list
+%endif
+        
     mov     al, LARGEST_DPT_SIZE
-    sub     dl, [RAMVARS.bFirstDrv]
+        
     mul     dl
     add     ax, BYTE RAMVARS_size
 
-    xchg    di, ax  ; Restore AX and put result in DI
+    xchg    di, ax                      ; Restore AX and put result in DI
     pop     dx
     ret
@@ -89 +107 @@
 ; IterateToMasterAtPortCallback
 ;   Parameters:
-;       CH:     Drive number
 ;       DX:     IDE Base Port address
 ;       DS:DI:  Ptr to DPT to examine
 ;   Returns:
-;       DL:     Drive number if correct DPT
 ;       CF:     Set if wanted DPT found
 ;               Cleared if wrong DPT
@@ -116 +132 @@
     pop     bx
     jne     SHORT ReturnWrongDPT
-    mov     dl, ch                              ; Return drive number in DL
 
 ReturnRightDPT:
@@ -187 +202 @@
 ;   Returns:
 ;       DS:DI:      Ptr to wanted DPT (if found)
+;                   If not found, points to first empty DPT
 ;       CF:         Set if wanted DPT found
 ;                   Cleared if DPT not found, or no DPTs present
@@ -195 +211 @@
 IterateAllDPTs:
     push    cx
-    mov     cx, [RAMVARS.wDrvCntAndFirst]
+
+    mov     cl, [RAMVARS.bDrvCnt]       
+    mov     ch, 0
+        
+    mov     di, RAMVARS_size            ; Point DS:DI to first DPT
+        
     jcxz    .NotFound                   ; Return if no drives
-    mov     di, RAMVARS_size            ; Point DS:DI to first DPT
+        
 ALIGN JUMP_ALIGN
 .LoopWhileDPTsLeft:
     call    si                          ; Is wanted DPT?
     jc      SHORT .AllDptsIterated      ;  If so, return
-    inc     ch                          ; Increment drive number
     add     di, BYTE LARGEST_DPT_SIZE   ; Point to next DPT
-    dec     cl                          ; Decrement drives left
-    jnz     SHORT .LoopWhileDPTsLeft
+    loop    .LoopWhileDPTsLeft
+        
 .NotFound:      
     clc                                 ; Clear CF since DPT not found
+        
 ALIGN JUMP_ALIGN
 .AllDptsIterated: