Document some hard-coded values

picosonic · Oct 23, 2023 · 644f963 · 644f963
1 parent acdc09f
commit 644f963
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/beeb/consts.asm b/beeb/consts.asm
@@ -12,10 +12,12 @@ BYTESPERLINE = (MAXX*2)
 MODE8BASE  = &5000
 
 ; Sideways RAM banks
+SWR_SLOTS = 16
 SWR_PAGE = &1100
 SWR_ROOMDATA = &11FF
 SWR_MOREDATA = &11FE
 ROM_SIZE16KB = 16*1024
+SWR_CACHE = ROMSBASE-ROM_SIZE16KB
 
 MACRO PAGE_ROOMDATA
   SEI:LDA SWR_ROOMDATA:STA ROMSEL:STA ROMSEL_CACHE:CLI

diff --git a/beeb/loader2.asm b/beeb/loader2.asm
@@ -32,7 +32,7 @@ ALIGN &100
   CPY #&FD:BEQ swrdone ; Stop if we've found 2 SWR
  
 .noswryet
-  INX:CPX #16:BNE findswr ; Keep looking until we get to slot 16
+  INX:CPX #SWR_SLOTS:BNE findswr ; Keep looking until we get to slot 16
 
   ; Re-select ROM (likely BASIC)
 .swrdone
@@ -54,7 +54,7 @@ ALIGN &100
   LDX #&00
 .swrcpyloop
   ; Copy a page of data
-  LDA &4000, X:STA ROMSBASE, X
+  LDA SWR_CACHE, X:STA ROMSBASE, X
   INX
   CPX #&00:BNE swrcpyloop
 
@@ -63,13 +63,13 @@ ALIGN &100
 
   ; See if src has got to the end
   LDA swrcpyloop+2
-  CMP #&80:BNE swrcpyloop
+  CMP #hi(ROMSBASE):BNE swrcpyloop
 
   ; Re-select ROM (likely BASIC)
   LDY ROMSEL_CACHE:STY ROMSEL
 
   ; Put back source/dest incase further copies are done
-  LDA #&40:STA swrcpyloop+2
+  LDA #hi(SWR_CACHE):STA swrcpyloop+2
   LDA #hi(ROMSBASE):STA swrcpyloop+5
 
   CLI