reloc: store ReadHandle and pHunks pointers in frame pointer

bootrom/reloc.S

@@ -1,5 +1,5 @@
 ; reloc.S
-; Modified from Open Source A4091.device by Stefan Reinauer and Chris Hooper - https://github.com/A4091/a4091-software
+; Modified from Open Source A4091.device by Stefan Reinauer and Chris Hooper - https://github.com/A4091/a3091-software
         INCLUDE "exec/memory.i"
         INCLUDE "lvo/exec_lib.i"
 
@@ -9,6 +9,12 @@
 
 NUM_ENTRIES EQU 5
 
+; Frame pointer offsets
+PHUNKS             EQU -4
+READHANDLE_TYPE    EQU -8
+READHANDLE_CURRENT EQU -12
+FP_SIZE            EQU READHANDLE_CURRENT
+
         ; API:
         ; Zorro ROM access:
         ;   a0: rombase
@@ -19,6 +25,7 @@ NUM_ENTRIES EQU 5
         public  _relocate
 _relocate
         movem.l d1-d7/a0-a6,-(sp)
+        link    a4,#FP_SIZE
 
         bsr     InitHandle
 
@@ -39,7 +46,7 @@ _relocate
         ; Go through hunk header and allocate all segments
         move.l  4,a6 ; execbase
 
-        move.l  pHunks(pc),a2   ; segment pointers
+        move.l  PHUNKS(a4),a2   ; segment pointers
         lea.l   4*NUM_ENTRIES(a2),a3        ; segment lengths
 .AllocateLoop
         moveq.l #MEMF_PUBLIC,d1
@@ -54,7 +61,7 @@ _relocate
         move.l  d0,(a2)+         ; segment pointer
         dbra    d7,.AllocateLoop
 
-        move.l  pHunks(pc),a5
+        move.l  PHUNKS(a4),a5
 .HunkLoop
         move.l  (a5),a0 ; current hunk
         bsr     RomFetch32
@@ -85,6 +92,7 @@ _relocate
         ENDIF
         bsr     .RelocateCleanup
         moveq.l #0,d0 ; NULL = Failure
+        unlk    a4
         movem.l (sp)+,d1-d7/a0-a6
         rts
 
@@ -129,16 +137,16 @@ _relocate
         move.l  d0,d2 ; num ; number of the hunk the offsets are to point into
 
         lsl.l   #2,d2 ; *4 ; offset from Hunks
-        move.l  pHunks(pc),a2
+        move.l  PHUNKS(a4),a2
         add.l   d2,a2 ; hunk number num
         move.l  (a2),d3 ; base address of hunk
 
 .Reloc32Tight
         bsr     RomFetch32
         ; get baseaddr + d0, add d3 to the data there.
-        move.l  a0,a4
+        move.l  a0,a3
-        add.l   d0,a4
+        add.l   d0,a3
-        add.l   d3,(a4)
+        add.l   d3,(a3)
         dbra    d1,.Reloc32Tight
 
         bra     .HunkReloc32
@@ -158,21 +166,21 @@ _relocate
         move.l  d0,d2 ; num ; number of the hunk the offsets are to point into
 
         lsl.l   #2,d2 ; *4 ; offset from Hunks
-        move.l  pHunks(pc),a2
+        move.l  PHUNKS(a4),a2
         add.l   d2,a2 ; hunk number num
         move.l  (a2),d3 ; base address of hunk
 
 .Reloc32ShortTight
         bsr     RomFetch16
         ; get baseaddr + d0, add d3 to the data there.
-        move.l  a0,a4
+        move.l  a0,a3
-        add.l   d0,a4
+        add.l   d0,a3
-        add.l   d3,(a4)
+        add.l   d3,(a3)
         dbra    d1,.Reloc32ShortTight
 
         bra     .HunkReloc32Short
 .HunkLoopPrep
-        lea     ReadHandle(pc),a2
+        lea     READHANDLE_CURRENT(a4),a2
         move.l  (a2),d0 ; align pointer to longword
         addq.l  #2,d0   ; in case we had an odd number
         and.l   #$fffffffc,d0  ; of relocations
@@ -202,17 +210,18 @@ _relocate
 
         bsr.s   CreateSegList
 
-        move.l  pHunks(pc),a0
+        move.l  PHUNKS(a4),a0
         move.l  (a0),d2
         subq.l  #4,d2
 
         bsr.s   .RelocateCleanup
         move.l  d2,d0
+        unlk    a4
         movem.l (sp)+,d1-d7/a0-a6
         rts
 
 .RelocateCleanup
-        move.l  pHunks(pc),a1
+        move.l  PHUNKS(a4),a1
         moveq.l #(8*NUM_ENTRIES),d0
         jsr     _LVOFreeMem(a6)
         rts
@@ -233,7 +242,7 @@ _relocate
 ;          +->|  |  |  | 0| |  |  |  | 0|
 ;             +--+--+--+--+ +--+--+--+--+
 CreateSegList:
-        move.l  pHunks(pc),a0
+        move.l  PHUNKS(a4),a0
 
 .NextSeg
         move.l  (a0),a1     ; Hunks[x]
@@ -269,10 +278,10 @@ RomFetch32
 
 RomFetch
         movem.l a0-a1/d1-d3,-(sp)
-        lea     ReadHandle(pc),a1
+        lea     READHANDLE_CURRENT(a4),a1
         move.l  (a1),a0
 
-        tst.l   4(a1)      ; access type Zorro?
+        tst.l   READHANDLE_TYPE(a4)      ; access type Zorro?
         bne.s   .RomFetchZ
 
         cmp.b   #3,d0
@@ -310,7 +319,7 @@ RomFetch
         rts
 
 InitHandle
-        ; initialize readhandle to beginning of device driver
+        ; initialize READHANDLE_CURRENT to beginning of device driver
         ; ROM_OFFSET needs to be multiplied by 4 because of the
         ; nibble mapped nature of the AutoConfig ROM.
         ; ROM_ADDRESS is passed in a0
@@ -320,24 +329,15 @@ InitHandle
         ENDIF
 
         add.l   d0,a0
-        lea     ReadHandle(pc),a1
+        move.l  a0,READHANDLE_CURRENT(a4)     ; memory location passed in a0
-        move.l  a0,(a1)  ; memory location passed in a0
+        move.l  d0,READHANDLE_TYPE(a4)   ; Set access type: 0 = memory, Zorro otherwise
-        move.l  d0,4(a1) ; Set access type: 0 = memory, Zorro otherwise
 
         moveq.l #(8*NUM_ENTRIES),d0
         move.l  #MEMF_PUBLIC|MEMF_CLEAR,d1
         jsr     _LVOAllocMem(a6)
-        lea     pHunks(pc),a1
+        move.l  d0,PHUNKS(a4)
-        move.l  d0,(a1)
         rts
 
-ReadHandle
-        dc.l    0 ; Current address
-        dc.l    0 ; 0=memory, otherwise Zorro
-
-pHunks
-        dc.l    0
-
         IFD HAVE_ERRNO
         public _rErrno
 _rErrno