Wack0 · MCJack123 · Jul 29, 2024 · Jul 29, 2024 · Jul 30, 2024
diff --git a/README.md b/README.md
@@ -6,9 +6,6 @@ This repository currently contains the source code for the ARC firmware and its
 * Power Macintosh G3 (Blue & White) *"Yosemite"*
 * Macintosh PowerBook G3 Bronze Keyboard *"Lombard"* 
 * Power Macintosh G4 PCI *"Yikes!"*
-
-The ARC firmware itself runs at a low enough level that it should be compatible with Old World systems using the same chipset too, but there is currently no loader for these systems; these are the following:
-
 * Power Macintosh G3 (beige)
 * Macintosh PowerBook G3 Series *"Wallstreet"*, *"PDQ"*
 
@@ -45,6 +42,7 @@ NT 3.51 RTM and higher. NT 3.51 betas (build 944 and below) will need kernel pat
 ### Partitioning Disk
 
 * Boot your PowerMac from the burned optical media. When you get to ARC firmware menu, go to `Run firmware setup`, then `Repartition disk for NT installation`.
+	* On an "Old World" machine (Power Mac G3 beige, PowerBook G3 Wallstreet/PDQ), boot the CD by holding Cmd+Opt+O+F to enter Open Firmware, type `boot ide1/disk\boot.xcf`, and press enter.
 * The disk partitioner will first let you enter partition size of the NT partition (up to the 16383x16x63 CHS limit, minus 32 MB ARC system partition + 1 MB for partition tables / MBR backup / OS 9 drivers / ARC environment variable storage, giving a maximum possible size of 8030 MB), then will drop to a menu allowing the creation of additional Mac partitions.
 	* If you choose an NT partition size over 2GB, the partition will be formatted to NTFS.
 	* After adding a partition to the list, the only way to remove from the list is by cancelling the operation and starting the partitioner again.
@@ -73,6 +71,12 @@ NT 3.51 RTM and higher. NT 3.51 betas (build 944 and below) will need kernel pat
 * If you chose to create an NT partition of over 2GB in size, errors will be found by the disk examination process which will require a reboot. Boot your PowerMac from the ARC firmware CD again and follow the steps to boot the NT4 text setup again.
 	* On the second attempt, disk examination will succeed, so just choose the `C:` partition again in the NT text setup partition selector.
 * Proceed through the rest of NT text and graphical setup as normal.
+* On an Old World system, you'll need to set the boot device manually.
+	* Reboot and hold Cmd+Opt+O+F to enter Open Firmware.
+	* Type `setenv boot-device ide0/disk@0:6\boot.xcf` to set the boot device.
+	* Type `reset-all` or press Ctrl+Cmd+Power to restart.
+	* You'll need to do this again if the PRAM gets reset (e.g. power is removed and PRAM battery is dead or removed).
+	* If you have Mac OS 8/9 working, you can also use the System Disk control panel to set the boot device. Select the `Power User` option, and select `Configure Manually` next to `Boot Device`. Then change it to `ide0/disk@0:6\boot.xcf` as shown above. Hit `Save` and reboot.
 
 ## Known issues
 
@@ -96,11 +100,11 @@ You need devkitPPC. Additionally, a `libgcc.a` compiled for `powerpcle` must be
 
 * Ensure `DEVKITPPC` environment variable is set to your devkitPPC directory, usually `/opt/devkitpro/devkitPPC`
 * Build the big endian libc: `cd baselibc ; make ; cd ..`
-* Build the ARC firmware loader: `cd arcloader_grackle ; make ; cd ..`
+* Build the ARC firmware loader: `cd arcloader_grackle ; make ; make oldworld ; cd ..`
 * Build the little endian libc: `cd arcgrackle/baselibc ; make ; cd ../..`
 * Build the ARC firmware itself: `cd arcgrackle ; make ; cd ..`
 
-Replace `stage1.elf` and `stage2.elf` inside the release image. For recreating the image from a folder dump, use your preferred tool to create a hybrid HFS+ISO image, make sure `System` folder is blessed and `BootX` file is of type `tbxi`.
+Replace `stage1.elf`, `boot.xcf`, and `stage2.elf` inside the release image. For recreating the image from a folder dump, use your preferred tool to create a hybrid HFS+ISO image, make sure `System` folder is blessed and `BootX` file is of type `tbxi`.
 
 Please note that `stage1.elf` must not be larger than 16KB and `stage2.elf` must not be larger than 224KB.
 
@@ -113,3 +117,4 @@ Please note that `stage1.elf` must not be larger than 16KB and `stage2.elf` must
 	* USB drivers in OpenBIOS were themselves adapted from [coreboot](https://github.com/coreboot/coreboot)
 * ISO9660 FS implementation inside ARC firmware is [lib9660](https://github.com/erincandescent/lib9660) with some modifications.
 * FAT FS implementation inside ARC firmware is [Petit FatFs](http://elm-chan.org/fsw/ff/00index_p.html) with some modifications.
+* `hack-coff.c` for XCOFF loaders is borrowed from the Linux kernel source.
diff --git a/arcgrackle/Makefile b/arcgrackle/Makefile
@@ -48,7 +48,7 @@ $(TARGET): $(OBJS)
 	@echo "  LINK      $@"
 	@$(CC) $(LDFLAGS) $(OBJS) $(LIBS) -o $@
 	@cp $(TARGET) $(TARGET:%.elf=%_unstripped.elf)
-	@strip $(TARGET)
+	@$(STRIP) $(TARGET)
 
 ifneq ($(LDSCRIPT),)
 $(TARGET): $(LDSCRIPT)

diff --git a/arcloader_grackle/Makefile b/arcloader_grackle/Makefile
@@ -19,6 +19,10 @@ LDFLAGS += -nostartfiles -nodefaultlibs -L../baselibc
 LDSCRIPT = of.ld
 TARGET = stage1.elf
 
+LDSCRIPT_XCOFF = of-xcoff.ld
+LDFLAGS_XCOFF := $(LDFLAGS)
+TARGET_XCOFF = boot
+
 FILES = $(wildcard source/*.S) $(wildcard source/*.c)
 OBJSx = $(FILES:source/%.S=build/%.o)
 OBJS = $(OBJSx:source/%.c=build/%.o)
@@ -33,11 +37,15 @@ OBJCOPY = $(PREFIX)objcopy
 RANLIB = $(PREFIX)ranlib
 STRIP = $(PREFIX)strip
 
+HOSTCC ?= gcc
+
 ifeq ($(NOMAPFILE),)
+LDFLAGS_XCOFF += -Wl,-Map,$(TARGET_XCOFF).map
 LDFLAGS += -Wl,-Map,$(TARGET).map
 endif
 
 ifneq ($(LDSCRIPT),)
+LDFLAGS_XCOFF += -Wl,-T$(LDSCRIPT_XCOFF)
 LDFLAGS += -Wl,-T$(LDSCRIPT)
 endif
 
@@ -46,11 +54,30 @@ DEPDIR = .deps
 all: $(TARGET)
 	@[ -d $(DIR_BUILD) ] || mkdir $(DIR_BUILD)
 
+oldworld: $(TARGET_XCOFF).xcf
+	@[ -d $(DIR_BUILD) ] || mkdir $(DIR_BUILD)
+
 $(TARGET): $(OBJS)
 	@echo "  LINK      $@"
 	@$(CC) $(LDFLAGS) $(OBJS) $(LIBS) -o $@
 	@cp $(TARGET) $(TARGET:%.elf=%_unstripped.elf)
-	@strip $(TARGET)
+	@$(STRIP) $(TARGET)
+
+$(TARGET_XCOFF).elf: $(OBJS)
+	@echo "  LINK      $@"
+	@$(CC) $(LDFLAGS_XCOFF) $(OBJS) $(LIBS) -o $@
+	@cp $(TARGET_XCOFF).elf $(TARGET_XCOFF)_unstripped.elf
+	@$(STRIP) $(TARGET_XCOFF).elf
+
+$(TARGET_XCOFF).xcf: $(TARGET_XCOFF).elf hack-coff
+	@echo "  OBJCOPY   $@"
+	@rm -f $@
+	@$(OBJCOPY) -O aixcoff-rs6000 -j .text -j .data -j .bss $< $@
+	@./hack-coff $@
+
+hack-coff: hack-coff.c
+	@echo "  HOSTCC    $@"
+	@$(HOSTCC) -o $@ $<
 
 ifneq ($(LDSCRIPT),)
 $(TARGET): $(LDSCRIPT)

diff --git a/arcloader_grackle/hack-coff.c b/arcloader_grackle/hack-coff.c
@@ -0,0 +1,79 @@
+/*
+ * hack-coff.c - hack the header of an xcoff file to fill in
+ * a few fields needed by the Open Firmware xcoff loader on
+ * Power Macs but not initialized by objcopy.
+ *
+ * Copyright (C) Paul Mackerras 1997.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include "rs6000.h"
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define AOUT_MAGIC 0x010b
+
+#define get_16be(x) ((((unsigned char *)(x))[0] << 8) + ((unsigned char *)(x))[1])
+#define put_16be(x, v) (((unsigned char *)(x))[0] = (v) >> 8, ((unsigned char *)(x))[1] = (v) & 0xff)
+#define get_32be(x) ((((unsigned char *)(x))[0] << 24) + (((unsigned char *)(x))[1] << 16) + (((unsigned char *)(x))[2] << 8) + ((unsigned char *)(x))[3])
+
+int main(int ac, char **av) {
+    int fd;
+    int i, nsect;
+    int aoutsz;
+    struct external_filehdr fhdr;
+    AOUTHDR aout;
+    struct external_scnhdr shdr;
+
+    if (ac != 2) {
+        fprintf(stderr, "Usage: hack-coff coff-file\n");
+        exit(1);
+    }
+    if ((fd = open(av[1], 2)) == -1) {
+        perror(av[2]);
+        exit(1);
+    }
+    if (read(fd, &fhdr, sizeof(fhdr)) != sizeof(fhdr)) goto readerr;
+    i = get_16be(fhdr.f_magic);
+    if (i != U802TOCMAGIC && i != U802WRMAGIC && i != U802ROMAGIC) {
+        fprintf(stderr, "%s: not an xcoff file\n", av[1]);
+        exit(1);
+    }
+    aoutsz = get_16be(fhdr.f_opthdr);
+    if (read(fd, &aout, aoutsz) != aoutsz) goto readerr;
+    put_16be(aout.o_sndata, 0);
+    put_16be(aout.o_snbss, 0);
+    put_16be(aout.o_sntext, 0);
+    put_16be(aout.o_sntoc, 0);
+    put_16be(aout.o_snentry, 0);
+    put_16be(aout.o_snloader, 0);
+    nsect = get_16be(fhdr.f_nscns);
+    for (i = 0; i < nsect; ++i) {
+        if (read(fd, &shdr, sizeof(shdr)) != sizeof(shdr)) goto readerr;
+        if (strcmp(shdr.s_name, ".text") == 0) {
+            put_16be(aout.o_sntext, i + 1);
+            put_16be(aout.o_snentry, i + 1);
+        } else if (strcmp(shdr.s_name, ".data") == 0) {
+            put_16be(aout.o_sndata, i + 1);
+        } else if (strcmp(shdr.s_name, ".bss") == 0) {
+            put_16be(aout.o_snbss, i + 1);
+        }
+    }
+    put_16be(aout.magic, AOUT_MAGIC);
+    if (lseek(fd, (long)sizeof(struct external_filehdr), 0) == -1 || write(fd, &aout, aoutsz) != aoutsz) {
+        fprintf(stderr, "%s: write error\n", av[1]);
+        exit(1);
+    }
+    close(fd);
+    exit(0);
+
+readerr:
+    fprintf(stderr, "%s: read error or file too short\n", av[1]);
+    exit(1);
+}
diff --git a/arcloader_grackle/of-xcoff.ld b/arcloader_grackle/of-xcoff.ld
@@ -0,0 +1,27 @@
+OUTPUT_FORMAT("elf32-powerpc")
+OUTPUT_ARCH(powerpc:common)
+
+ENTRY(StartAixCall)
+
+SECTIONS {
+	. = 0x00050000;
+	__text_start = .;
+
+	.text : { *(.text) *(.text.*) *(.rodata) KEEP(*(.rodata.StartAixCall)); *(.rodata.*) }
+
+	. = ALIGN(4);
+
+	.sdata : { *(.sdata) *(.sdata.*) }
+	.data : { *(.data) *(.data.*) }
+
+	. = ALIGN(32);
+	__self_end = .;
+
+	__bss_start = .;
+	.bss : { *(.bss .bss.*) } :NONE = 0
+	.sbss : { *(.sbss) }
+	__bss_end = .;
+
+	. = ALIGN(32);
+	_end = .;
+}