Changeset 600 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS

Timestamp:

Jul 22, 2018, 6:12:12 AM (6 years ago)

Author:

Tomi Tilli

Message:

Hotkeybar timer tick handler now keeps interrupts disabled and updates on every fourth call.

Location:

trunk/XTIDE_Universal_BIOS

Files:

• Inc/BootVars.inc (modified) (1 diff)
• Src/Menus/HotkeyBar.asm (modified) (5 diffs)

trunk/XTIDE_Universal_BIOS/Inc/BootVars.inc

@@ -58 +58 @@
 ; Bit defines for HOTKEYVARS.bFlags
 FLG_HOTKEY_HD_FIRST         EQU     (1<<0)  ; First try to boot from HDD, then FDD
-FLG_HOTKEY_UPDATING         EQU     (1<<1)  ; Hotkeybar update in progress
 
 %endif ; MODULE_HOTKEYS

trunk/XTIDE_Universal_BIOS/Src/Menus/HotkeyBar.asm

@@ -47 +47 @@
     push    ax
 %endif
-    sti         ; Enable interrupts (is this really necessary? Do we lose key inputs if we keep interrupts disabled?)
-                ; There would be no need for FLG_HOTKEY_UPDATING if we can keep interrupts disabled during whole update.
+
+    ;!!! Keep interrupts disabled so there won't be another
+    ; timer tick call before we are ready
 
     LOAD_BDA_SEGMENT_TO es, ax
@@ -57 +58 @@
     call far [es:BOOTVARS.hotkeyVars+HOTKEYVARS.fpPrevTimerHandler]
 
-    ; Do not start updating if update is already in progress (do we need this on AT systems?)
-    test    BYTE [es:BOOTVARS.hotkeyVars+HOTKEYVARS.bFlags], FLG_HOTKEY_UPDATING
+    ; Update Hotkeybar (process key input and draw) every fourth tick
+    test    BYTE [es:BDA.dwTimerTicks], 11b
     jnz     SHORT .ReturnFromHandler
-
-    ; Update Hotkeybar (process key input and draw)
-%ifndef USE_AT  ; Ease XT systems a bit by updating every other timer tick
-    call    TimerTicks_ReadFromBdaToAX
-    shr     ax, 1
-    jnc     SHORT .ReturnFromHandler
-%endif
-    or      BYTE [es:BOOTVARS.hotkeyVars+HOTKEYVARS.bFlags], FLG_HOTKEY_UPDATING
     call    UpdateDuringDriveDetection
-    and     BYTE [es:BOOTVARS.hotkeyVars+HOTKEYVARS.bFlags], ~FLG_HOTKEY_UPDATING
 
 .ReturnFromHandler:
@@ -150 +142 @@
     ; Clear CH if floppy drive is selected for boot
     mov     ch, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.bFlags]
-    and     ch, FLG_HOTKEY_HD_FIRST
+    ;and        ch, FLG_HOTKEY_HD_FIRST; Not needed until more flags added
     call    FormatDriveHotkeyString
 
@@ -169 +161 @@
     mov     ah, ANGLE_QUOTE_RIGHT
     mov     cx, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.wHddLetterAndFlags]  ; Letter to CL, flags to CH
-    and     ch, FLG_HOTKEY_HD_FIRST
+    ;and        ch, FLG_HOTKEY_HD_FIRST ; Not needed until more flags added
     xor     ch, FLG_HOTKEY_HD_FIRST     ; Clear CH if HD is selected for boot, set otherwise
     mov     di, g_szHDD
@@ -573 +565 @@
 HotkeyBar_GetBootDriveNumbersToDX:
     mov     dx, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.wFddAndHddLetters]
+
+    ; HotkeyBar_GetBootDriveNumbersToDX is called when all drives are detected and
+    ; drive letters are known.
+    ; Replace unavailable hard drive letter with first hard drive.
+    ; If we have boot menu, it will be displayed instead.
+%ifndef MODULE_BOOT_MENU
+    call    BootVars_GetLetterForFirstHardDriveToAX
+    mov     ah, al
+    add     al, [es:BDA.bHDCount]   ; AL now contains first unavailable HD letter
+    cmp     dh, al                  ; Unavailable drive?
+    jb      SHORT .ValidHardDriveLetterInDH
+    mov     dh, ah                  ; Replace unavailable drive with first drive
+.ValidHardDriveLetterInDH:
+%endif
+
     test    BYTE [es:BOOTVARS.hotkeyVars+HOTKEYVARS.bFlags], FLG_HOTKEY_HD_FIRST
-    jnz     .noflip
+    jnz     SHORT .noflip
     xchg    dl, dh
 .noflip: