From 8eed2bd31aab3bc6c013f52b44db84d30fb24b19 Mon Sep 17 00:00:00 2001
From: Christophe Parent <christopheparent@thatspaceandtime.org>
Date: Fri, 29 Dec 2023 00:18:08 -0800
Subject: [PATCH] Inline CopyChars subroutine back to Bank 3

---
 src/linker.cfg |  1 -
 src/main.asm   | 49 ++++++++++++++++++++-----------------------------
 2 files changed, 20 insertions(+), 30 deletions(-)

diff --git a/src/linker.cfg b/src/linker.cfg
index ac83dba..ce569d2 100644
--- a/src/linker.cfg
+++ b/src/linker.cfg
@@ -20,7 +20,6 @@ SEGMENTS {
     AREADATA:    load = PRG1, type = ro,  optional = yes;
     ENEMYDATA:   load = PRG1, type = ro,  optional = yes;
     CHARS:       load = PRG2, type = ro,  optional = yes;
-    COPYCHARS:   load = PRG2, type = ro,  optional = yes;
     SOUNDENGINE: load = PRG2, type = ro,  optional = yes;
     BANK3:       load = PRG3, type = ro,  optional = yes;
     BANKSWITCH:  load = PRG3, type = ro,  optional = yes;
diff --git a/src/main.asm b/src/main.asm
index af69758..66dfa6b 100644
--- a/src/main.asm
+++ b/src/main.asm
@@ -714,7 +714,7 @@ ColdBoot:
     jsr MoveAllSpritesOffscreen
     jsr InitializeNameTables    ; initialize both name tables
     inc DisableScreenFlag       ; set flag to disable screen output
-    jsr CopyCharsBankSwitch
+    jsr CopyChars               ; Copy graphic tiles to CHR RAM
     lda Mirror_PPU_CTRL_REG1
     ora #%10000000              ; enable NMIs
     jsr WritePPUReg1
@@ -17340,11 +17340,27 @@ EnemyDataBankSwitch:
     ldx XStore
     rts
 
-; Graphic tiles and the graphics init copy routine are located in Bank 2; we switch back to Bank 0 when we are done
-CopyCharsBankSwitch:
+; Graphic tiles are located in Bank 2; we switch back to Bank 0 when we are done
+CopyChars:
     ldx #$02
     jsr BankSwitch
-    jsr CopyChars
+    lda #<Chars       ; load the source address into a pointer in zero page
+    sta CharsCopy
+    lda #>Chars
+    sta CharsCopy+1
+    ldy #$0           ; starting index into the first page
+    sty PPU_CTRL_REG2 ; turn off rendering just in case
+    sty PPU_ADDRESS   ; load the destination address into the PPU
+    sty PPU_ADDRESS
+    ldx #$20          ; number of 256-byte pages to copy
+LoopCopyChars:
+    lda (CharsCopy),y ; copy one byte
+    sta PPU_DATA
+    iny
+    bne LoopCopyChars ; repeat until we finish the page
+    inc CharsCopy+1   ; go to the next page
+    dex
+    bne LoopCopyChars ; repeat until we've copied enough pages
     ldx #$00
     jsr BankSwitch
     rts
@@ -17382,28 +17398,3 @@ BankTable:
 
 Chars:
     .incbin "chars.bin"
-
-;-------------------------------------------------------------------------------------
-; GRAPHICS INIT LOADING
-
-.segment "COPYCHARS"
-
-CopyChars:
-    lda #<Chars       ; load the source address into a pointer in zero page
-    sta CharsCopy
-    lda #>Chars
-    sta CharsCopy+1
-    ldy #$0           ; starting index into the first page
-    sty PPU_CTRL_REG2 ; turn off rendering just in case
-    sty PPU_ADDRESS   ; load the destination address into the PPU
-    sty PPU_ADDRESS
-    ldx #$20          ; number of 256-byte pages to copy
-LoopCopyChars:
-    lda (CharsCopy),y ; copy one byte
-    sta PPU_DATA
-    iny
-    bne LoopCopyChars ; repeat until we finish the page
-    inc CharsCopy+1   ; go to the next page
-    dex
-    bne LoopCopyChars ; repeat until we've copied enough pages
-    rts