Changeset 241 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Inc

Timestamp:

Feb 9, 2012, 11:08:59 AM (13 years ago)

Author:

gregli@…

google:author:

gregli@hotmail.com

Message:

Space optimizations in the Boot Menu and BootInfo routines, taking advantage of nested %s. Optimization in the init of RamVars to avoid writing the signature twice. Preparing for addition of serial floppy support, starting to break the assumption that our drives are always 80h or higher.

File:

• trunk/XTIDE_Universal_BIOS/Inc/BootVars.inc (modified) (1 diff)

trunk/XTIDE_Universal_BIOS/Inc/BootVars.inc

@@ -13 +13 @@
 LEN_BOOTNFO_DRV     EQU     26      ; Bytes reserved for drive name
 struc BOOTNFO
+    .szDrvName      resb    LEN_BOOTNFO_DRV     ; Drive name
+                    resb    2       ; Zero word (ensures string terminates)
     .twSectCnt      resb    6       ; Total user addressable sectors
-    .szDrvName      resb    LEN_BOOTNFO_DRV+1   ; Drive name
-                    resb    1       ; Alignment
+                    resb    2       ; padding to make BOOTNFO size an even multiple of DPT size
 endstruc
+
+DPT_BOOTNFO_SIZE_MULTIPLIER  equ    BOOTNFO_size / LARGEST_DPT_SIZE
+
+%ifndef CHECK_FOR_UNUSED_ENTRYPOINTS                
+
+%if BOOTNFO_size % LARGEST_DPT_SIZE <> 0
+%error "BOOTNFO's size must be an even multiple of DPT's size.  Add or remove padding at the bottom of BOOTNFO to bring the two sizes into alignment.  As BOOTNFO is only used at boot time, with plenty of memory to consume, it is OK to waste some space here."
+%endif
+
+%if BOOTNFO.szDrvName <> 0
+%error "BOOTNFO.szDrvName is assumed to be the first member of struc BOOTNFO, in BootMenuPrint_RefreshItem"
+%endif
+
+%if BOOTNFO.szDrvName + LEN_BOOTNFO_DRV + 2 <> BOOTNFO.twSectCnt
+%error "BOOTNFO.twSectCnt is assumed to come immediately after BOOTNFO.szDrvName (with zero padding), in BootInfo_CreateForHardDisk"
+%endif
+
+%endif