Changeset 230 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/Tools/Address.asm

Timestamp:

Jan 29, 2012, 11:22:19 PM (12 years ago)

Author:

krille_n_@…

google:author:

krille_n_@hotmail.com

Message:

Changes to XTIDE Universal BIOS:

• Some small optimizations

File:

• trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/Tools/Address.asm (modified) (2 diffs)

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/Tools/Address.asm

@@ -86 +86 @@
 Address_OldInt13hAddressToIdeAddress:
         call    Address_ExtractLCHSparametersFromOldInt13hAddress
-            
+
         AccessDPT_GetUnshiftedAddressModeToALZF
-        
-;;; 0: ADDR_DPT_LCHS        
-        jz      DoNotConvertLCHS    
-        
+
+;;; 0: ADDR_DPT_LCHS
+        jz      DoNotConvertLCHS
+
 ;;; 1: ADDR_DPT_PCHS
-        ; 
+        ;
         ; Since we are only checking for zero, we can do our math in the high order bits,
         ; in this case effectively subtracting 1 from the address mode.
         ;
         sub     al,(1<<ADDRESSING_MODE_FIELD_POSITION)
-        jz      ConvertLCHStoPCHS   
+        jz      ConvertLCHStoPCHS
 
-;;; 2: ADDR_DPT_LBA28 and 3: ADDR_DPT_LBA48             
-        ; Fall through to ConvertLCHStoLBARegisterValues  
-        
+;;; 2: ADDR_DPT_LBA28 and 3: ADDR_DPT_LBA48
+        ; Fall through to ConvertLCHStoLBARegisterValues
+
 ;---------------------------------------------------------------------
 ; Converts LCHS parameters to 28-bit LBA address.
@@ -129 +129 @@
     ; cylToSeek*headsPerCyl (18-bit result)
     mov     ax, cx                  ; Copy Cylinder number to AX
+    ; We could save a byte here by using CWD instead of the XOR DH, DH in eMOVZX
+    ; but I'm not sure how that would affect speed.
+
     eMOVZX  dx, BYTE [di+DPT.bLbaHeads]
     mul     dx                      ; DX:AX = cylToSeek*headsPerCyl