reloc.s: optimize for size.

1 files changed, 28 insertions, 9 deletions

diff --git a/reloc.s b/reloc.s
index 3702430..530e303 100644
--- a/reloc.s
+++ b/reloc.s
@@ -1,4 +1,8 @@
 
+; uncomment to enable user-friendly "MEMLO is too high" error.
+; adds ~80 bytes to the code size (40% larger).
+ ;verbose_memlo_check = 1
+
  .export _main
  .include "atari.inc"
 
@@ -39,6 +43,7 @@ memlo_00:
 
  bcs memlo_ok
 
+ .ifdef verbose_memlo_check
  ; whoops, MEMLO is too high
 whoops:
  ldx #0
@@ -61,22 +66,31 @@ exitwait:
  lda #0
  sta COLOR2
  rts
+ .else
+ lda #$40
+ sta COLOR2
+freeze: bne freeze
+ .endif
 
 memlo_ok:
- ; adjust addresses before moving the code
+ ; adjust addresses before moving the code.
+ ; point to the relocation table...
  lda #<table
  sta table_ptr
  lda #>table
  sta table_ptr+1
 
 fixup_addrs:
+ ; walk the reloc table
  ldy #1
  lda (table_ptr),y
  sta code_ptr+1
  dey
  lda (table_ptr),y
  sta code_ptr
- inc table_ptr  ; point to next entry
+
+ ; point to next table entry
+ inc table_ptr
  bne tp1ok
  inc table_ptr+1
 tp1ok:
@@ -84,7 +98,8 @@ tp1ok:
  bne tp2ok
  inc table_ptr+1
 tp2ok:
- ora code_ptr+1 ; quit if we hit $0000 in the table
+
+ ora code_ptr+1 ; A still has code_ptr, quit if we hit $0000 in the table
  beq fixup_done
  lda (code_ptr),y ; Y still 0
  sec
@@ -127,7 +142,6 @@ move_loop:
  dex
  bne move_loop
 
-
  ; bump MEMLO to point one byte past the end of the moved code.
  lda code_end
  sec
@@ -136,12 +150,13 @@ move_loop:
  lda code_end+1
  sbc code_start+1
  sta code_end+1
- inc code_end
- bne ceok
- inc code_end+1 ; code_end is now the code length + 1 byte
-ceok:
+ ;inc code_end
+ ;bne ceok
+ ;inc code_end+1 ; code_end is now the code length + 1 byte
+;ceok:
  lda code_end
- clc
+ ;clc
+ sec
  adc MEMLO
  sta MEMLO
  lda code_end+1
@@ -175,11 +190,15 @@ do_init:
 done:
  rts
 
+ .ifdef verbose_memlo_check
 whoops_msg: .byte "MEMLO is too high! Press any key to exit.", EOL
  whoops_len = (*-whoops_msg)
+ .endif
 
 end_addr:
 
+ .out .sprintf("reloc.s code size $%04x (%d)", (* - start_addr), (* - start_addr))
+
 ; this was for testing only. mkrelocxex.c adds the init address.
 ; .word INITAD
 ; .word INITAD+1