From e3c9c7b6421d8106c7c4b20ff7d3969d8c431015 Mon Sep 17 00:00:00 2001
From: "A.M. Rowsell" <amr@frzn.dev>
Date: Sun, 21 Dec 2025 14:40:15 -0500
Subject: [PATCH] linker: ensured .bss comes after .data, and added map file
 output

---
 .gitignore | 2 +-
 Makefile   | 7 ++++---
 boot.asm   | 4 ++++
 linker.cmd | 3 ++-
 4 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/.gitignore b/.gitignore
index 940421a..35c765e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,6 @@
 *.srec
 *.s19
 *.elf
-
+*.map
 AGENTS.md
 .pre-commit-config.yaml
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 37e0284..9fe9a35 100644
--- a/Makefile
+++ b/Makefile
@@ -2,9 +2,10 @@
 # SPDX-FileCopyrightText: (c) 2025 A.M. Rowsell
 ASM=vasm_z80_std
 LINK=vlink
+MAP=zone.map
 
 ASMFLAGS=-Fvobj
-LINKFLAGS=-b ihex -T linker.cmd
+LINKFLAGS=-b ihex -T linker.cmd -M
 
 all: zone.hex
 
@@ -21,9 +22,9 @@ boot.o: boot.asm
 	$(ASM) $(ASMFLAGS) -o $@ $<
 
 zone.hex: float.o vectorTable.o zone.o boot.o linker.cmd
-	$(LINK) $(LINKFLAGS) -o $@ float.o vectorTable.o zone.o boot.o
+	$(LINK) $(LINKFLAGS) -o $@ float.o vectorTable.o zone.o boot.o > $(MAP)
 
 clean:
-	rm -f float.o vectorTable.o zone.o boot.o zone.hex
+	rm -f float.o vectorTable.o zone.o boot.o zone.hex $(MAP)
 
 .PHONY: all clean
diff --git a/boot.asm b/boot.asm
index 92c0e4a..2ebcd44 100644
--- a/boot.asm
+++ b/boot.asm
@@ -5,6 +5,10 @@
 .global os_warm_boot
 .extern os_main_loop
 
+; ==================================
+; This is the cold boot entry point!
+; It is linked to land at 0xC3C3
+; ==================================
 zone_setup:
     ld sp, 0x6FFF
     jp os_main_loop
diff --git a/linker.cmd b/linker.cmd
index 9d2be01..67b30a6 100644
--- a/linker.cmd
+++ b/linker.cmd
@@ -6,5 +6,6 @@ SECTIONS
   .boot     0xC3C3 : { *(.boot) *(boot) }
   .vectors  0xF000 : { *(.vectors) }
   .data     0x7000 : { *(.data) }
-  .bss            : { *(.bss)  }
+  __data_end = .;
+  .bss      __data_end : { *(.bss)  }
 }