Switch to labels instead of absolute addresses for ProDOS globals

applecorn.s

@@ -40,8 +40,21 @@ RSTV        EQU   $3F2
 * IRQ vector
 A2IRQV      EQU   $3FE
 
+* ProDOS Global Page equates
 * MLI entry point
 MLI         EQU   $BF00
+* Machine ID byte
+MACHID      EQU   $BF98
+* Versioning bytes
+IBAKVER     EQU   $BFFC
+IVERSION    EQU   $BFFD
+* System BitMap locations
+P8BMAP0007  EQU   $BF58
+P8BMAP080F  EQU   $BF59
+P8BMAP2027  EQU   $BF5C
+P8BMAP282F  EQU   $BF5D
+P8BMAP3037  EQU   $BF5E
+P8BMAP383F  EQU   $BF5F
 
 * IO Buffer for reading file (1024 bytes)
 IOBUF0      EQU   $0C00       ; For loading/saving, OSFILE, *.

mainmem.init.s

@@ -55,7 +55,7 @@ RTSINST      LDA   CMDPATH
 
 * Disconnect /RAM ramdrive to avoid aux corruption
 * Stolen from Beagle Bros Extra K
-DISCONN      LDA   $BF98
+DISCONN      LDA   MACHID
              AND   #$30
              CMP   #$30
              BNE   :S1

mainmem.ldr.s

@@ -15,9 +15,9 @@ SYSTEM      LDX   #$FF             ; Init stack pointer
             TXS
 
             LDA   #$00
-            STA   $BFFC            ; IBAKVER (minimum P8 version)
+            STA   IBAKVER          ; Minimum compatible P8 version
             LDA   #$01
-            STA   $BFFD            ; IVERSION (version of me)
+            STA   IVERSION         ; Version of .SYSTEM program
 
             SED                    ; Check for 65C02
             LDA   #$99
@@ -27,21 +27,21 @@ SYSTEM      LDX   #$FF             ; Init stack pointer
             BPL   GOODCPU
             JMP   UNSUPPORTED
 
-GOODCPU     LDA   $BF98            ; MACHID
+GOODCPU     LDA   MACHID
             AND   #$F2             ; Clear bits 0,2,3
             CMP   #$B2             ; Are we on a //e or //c w/ 80col and 128K or a IIgs?
             BEQ   SUPPORTED        ; Supported machine
             JMP   UNSUPPORTED      ; Unsupported machine
 
 SUPPORTED   LDA   #$DF             ; Protect pages $0,$1,and $3-$7
-            STA   $BF58
+            STA   P8BMAP0007
             LDA   #$F0             ; Protect pages $8-$B
-            STA   $BF59
+            STA   P8BMAP080F
             LDA   #$FF             ; Protect HGR1
-            STA   $BF5C
-            STA   $BF5D
-            STA   $BF5E
-            STA   $BF5F
+            STA   P8BMAP2027
+            STA   P8BMAP282F
+            STA   P8BMAP3037
+            STA   P8BMAP383F
             JMP   START
 
 UNSUPPORTED JSR   HOME
@@ -61,7 +61,7 @@ UNSUPKEY    LDA   $C000
             DW    UNSUPQPARM
 UNSUPQPARM  DB    $04,$00,$00,$00,$00,$00,$00
 
-UNSUPMSG    ASC   "APPLECORN REQUIRES AN APPLE IIGS, APPLE"
+UNSUPMSG    ASC   "APPLECORN REQUIRES AN APPLE IIGS, APPLE", 8D
             ASC   "//C, OR ENHANCED APPLE //E WITH AN", 8D
             ASC   "80-COLUMN CARD AND AT LEAST 128K", 8D, 8D
             ASC   "PRESS ANY KEY TO QUIT TO PRODOS", 00