From 83d15869b5ff498076eb875c214693fb56474462 Mon Sep 17 00:00:00 2001
From: Matt Harlum <matt@harlum.net>
Date: Wed, 30 Oct 2024 06:31:39 +0000
Subject: [PATCH] Replace mungerom.c with a python script

---
 bootrom/.gitignore  |  3 ++-
 bootrom/Makefile    |  8 ++------
 bootrom/atbusrom.ld |  6 +++++-
 bootrom/mungerom.c  | 33 ---------------------------------
 bootrom/mungerom.py | 26 ++++++++++++++++++++++++++
 bootrom/rom.ld      |  4 ++++
 6 files changed, 39 insertions(+), 41 deletions(-)
 delete mode 100644 bootrom/mungerom.c
 create mode 100755 bootrom/mungerom.py

diff --git a/bootrom/.gitignore b/bootrom/.gitignore
index cb945c0..fb1694a 100644
--- a/bootrom/.gitignore
+++ b/bootrom/.gitignore
@@ -5,4 +5,5 @@ at
 **/*.out
 **/*.device
 **/*.hunk
-**/*.adf
\ No newline at end of file
+**/*.adf
+*.pyc
\ No newline at end of file
diff --git a/bootrom/Makefile b/bootrom/Makefile
index 8723e05..89ac038 100644
--- a/bootrom/Makefile
+++ b/bootrom/Makefile
@@ -14,10 +14,6 @@ OBJS = $(SRCS:%.S=$(OBJDIR)/%.o)
 
 all:	../$(PROJECT).rom ../$(PROJECT)-atbus.rom ../$(PROJECT)-word.rom
 
-$(OBJDIR)/mungerom: mungerom.c
-	@mkdir -p $(OBJDIR)
-	$(CC) $< -Wall -o $@
-
 # Nibble-wide boot loader with Byte-wide driver
 $(OBJDIR)/%.o: %.S
 	@mkdir -p $(OBJDIR)
@@ -34,9 +30,9 @@ $(OBJDIR)/bootldr:	$(OBJDIR)/bootldr.o
 $(OBJDIR)/bootldr-word:	$(OBJDIR)/bootldr-word.o
 	$(LINKER) $(LINKFLAGS) -o $@ $^
 
-$(OBJDIR)/bootnibbles: $(OBJDIR)/bootldr $(OBJDIR)/mungerom
+$(OBJDIR)/bootnibbles: $(OBJDIR)/bootldr mungerom.py
 	@mkdir -p $(OBJDIR)
-	./obj/mungerom
+	./mungerom.py
 
 $(OBJDIR)/assets.o: assets.S $(OBJDIR)/bootnibbles ../lide.device
 
diff --git a/bootrom/atbusrom.ld b/bootrom/atbusrom.ld
index 65ecf89..53beef7 100644
--- a/bootrom/atbusrom.ld
+++ b/bootrom/atbusrom.ld
@@ -2,8 +2,12 @@ SECTIONS {
     rom = .;
     .bootldr 0x00: {
         *(BOOTLDR);
-        RESERVE(0x1000-.);
+        RESERVE(0x800-.);
     } = 0xFFFF
+    .reserved 0x800: {
+        FILL8(0xFF);
+        RESERVE(0x1000-.);
+    }
     .device 0x1000 : {
         *(DEVICE)
     }
diff --git a/bootrom/mungerom.c b/bootrom/mungerom.c
deleted file mode 100644
index 55b32f9..0000000
--- a/bootrom/mungerom.c
+++ /dev/null
@@ -1,33 +0,0 @@
-#include <stdio.h>
-#include <stdint.h>
-#include <stdlib.h>
-
-// Chop up the bootrom section into nibbles for Z2 nibblewise bootrom  - Kick 1.3 and below don't support DAC_BYTEWIDE :(
-// The device driver will be loaded bytewise by reloc
-int main () {
-  FILE *fh = fopen("obj/bootldr","r");
-
-  char *src,*dst = NULL;
-
-  src = malloc(2048);
-  dst = malloc(4096);
-
-  int len = fread(src,1,2048,fh);
-  fclose(fh);
-  for (int i=0; i<len;i++) {
-    char hi = *(src+i) & 0xF0;
-    char lo = *(src+i) & 0x0F;
-    lo <<= 4;
-    dst[i<<1]     = hi;
-    dst[(i<<1)+1] = lo;
-  }
-
-  fh = fopen("obj/bootnibbles","w");
-
-  fwrite(dst,1,len*2,fh);
-
-  fclose(fh);
-
-  free(src);
-  free(dst);
-}
diff --git a/bootrom/mungerom.py b/bootrom/mungerom.py
new file mode 100755
index 0000000..45eca94
--- /dev/null
+++ b/bootrom/mungerom.py
@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+import os
+import sys
+# Chop up the bootrom section into nibbles for Z2 nibblewise bootrom  - Kick 1.3 and below don't support DAC_BYTEWIDE :(
+# The device driver itself will be loaded bytewise by reloc
+
+c_bright_red = "\033[1;31m"
+c_reset = "\033[0m"
+
+# On the AT-Bus the ROM is not selected between $1000-$1FFF
+# So we need to fit the boot rom under this limit
+size_limit = 1024
+
+with open("obj/bootldr", "rb") as s:
+    romSize = os.fstat(s.fileno()).st_size
+    
+    if romSize > size_limit:
+        print(f"{c_bright_red}bootldr too large, Size: {romSize} Limit: {size_limit}{c_reset}")
+        sys.exit(1)
+
+    rom = s.read()
+    
+    with open("obj/bootnibbles","wb") as d:
+        for b in rom:
+            d.write(bytes([(b & 0xF0) | 0x0F]))
+            d.write(bytes([((b << 4) & 0xF0) | 0x0F]))
diff --git a/bootrom/rom.ld b/bootrom/rom.ld
index 7e3a409..31aaefa 100644
--- a/bootrom/rom.ld
+++ b/bootrom/rom.ld
@@ -5,6 +5,10 @@ SECTIONS {
     } = 0xFFFF
     .bootldr 0x04: {
         *(BOOTLDR);
+        RESERVE(0x800-.);
+    }
+    .reserved 0x800: {
+        FILL8(0xFF);
         RESERVE(0x1000-.);
     }
     .device 0x1000 : {