Changeset 116 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Boot

Timestamp:

Feb 26, 2011, 11:55:06 PM (14 years ago)

Author:

krille_n_@…

google:author:

krille_n_@hotmail.com

Message:

Changes to all parts of the project:

• Removed a redundant macro (HPIO_NORMALIZE_PTR)
• Deleted XTIDE_Universal_BIOS/Inc/BiosData.inc since that was also redundant.
• Size optimization: Changed the LOAD_BDA_SEGMENT_TO macro to use the stack on 186+ processors (the old behaviour can still be used where needed).
• Made other minor size optimizations and cleanups to various functions, mostly in the Int13h handler.

Location:

trunk/XTIDE_Universal_BIOS/Src/Boot

Files:

• BootMenuPrintCfg.asm (modified) (2 diffs)
• BootVars.asm (modified) (5 diffs)

trunk/XTIDE_Universal_BIOS/Src/Boot/BootMenuPrintCfg.asm

@@ -99 +99 @@
     xchg    ax, bx      ; Store BX to AX
     eMOVZX  bx, BYTE [cs:si+IDEVARS.bBusType]
-    mov     bx, [cs:bx+.rgwBusTypeValues]   ; Char to BL, Int to BH 
+    mov     bx, [cs:bx+.rgwBusTypeValues]   ; Char to BL, Int to BH
     eMOVZX  dx, bh
     push    bx          ; Push character
@@ -191 +191 @@
     mov     dl, [di+DPT.bDrvNum]        ; Load Drive number to DL
     call    BootInfo_GetOffsetToBX      ; ES:BX now points...
-    LOAD_BDA_SEGMENT_TO es, ax          ; ...to BOOTNFO
+    LOAD_BDA_SEGMENT_TO es, ax, !       ; ...to BOOTNFO
     mov     al, [di+DPT.bIdeOff]
     xchg    si, ax                      ; CS:SI now points to IDEVARS

trunk/XTIDE_Universal_BIOS/Src/Boot/BootVars.asm

@@ -28 +28 @@
 ; POST stack is not large enough when DPTs are stored to 30:0h.
 ;
+; Note regarding LOAD_BDA_SEGMENT_TO: If you force the use of SP
+; then you also have to unconditionally enable the CLI/STI pair.
+; The reason for this is that only some buggy 808x CPU:s need the
+; CLI/STI instruction pair when changing stacks. Other CPU:s disable
+; interrupts automatically when SS is modified for the duration of
+; the immediately following instruction to give time to change SP.
+;
 ; BootVars_SwitchToBootMenuStack
 ;   Parameters:
@@ -39 +46 @@
 BootVars_SwitchToBootMenuStack:
     pop     ax                          ; Pop return address
+%ifndef USE_186
     cli                                 ; Disable interrupts
+%endif
     LOAD_BDA_SEGMENT_TO ss, sp
     mov     sp, BOOTVARS.rgbMnuStack    ; Load offset to stack
+%ifndef USE_186
     sti                                 ; Enable interrupts
+%endif
     jmp     ax
 
@@ -48 +59 @@
 ;--------------------------------------------------------------------
 ; Restores SS and SP to initial boot loader values.
+;
+; Before doing any changes, see the note regarding
+; LOAD_BDA_SEGMENT_TO in BootVars_SwitchToBootMenuStack
 ;
 ; BootVars_SwitchBackToPostStack
@@ -60 +74 @@
 BootVars_SwitchBackToPostStack:
     pop     ax                          ; Pop return address
+%ifndef USE_186
     cli                                 ; Disable interrupts
+%endif
     LOAD_BDA_SEGMENT_TO ss, sp
 %ifndef USE_386
@@ -68 +84 @@
     lss     sp, [ss:BOOTVARS.dwPostStack]
 %endif
+%ifndef USE_186
     sti                                 ; Enable interrupts
+%endif
     jmp     ax