Findings on booting Mac OS 9.2 - OpenBIOS

2 May 2016

I made a patch that prints everything that (evaluate) does, hoping it would tell me where execution stopped in the boot script. Here is the patch:
Index: forth/bootstrap/interpreter.fs
===================================================================

--- forth/bootstrap/interpreter.fs	(revision 1395)
+++ forth/bootstrap/interpreter.fs	(working copy)
@@ -151,6 +151,7 @@
   ;
: (evaluate) ( str len -- ??? )
+   2dup fprintk
   save-source
   -1 ['] source-id (to)
   dup
Index: kernel/bootstrap.c
===================================================================
--- kernel/bootstrap.c	(revision 1395)
+++ kernel/bootstrap.c	(working copy)
@@ -89,7 +89,7 @@
    "here", "here!", "dobranch", "do?branch", "unaligned-w@",
    "unaligned-w!", "unaligned-l@", "unaligned-l!", "ioc@", "iow@",
    "iol@", "ioc!", "iow!", "iol!", "i", "j", "call", "sys-debug",
-	"$include", "$encode-file", "(debug", "(debug-off)"
+	"$include", "$encode-file", "(debug", "(debug-off)", "fprintk"
 };
/*
Index: kernel/forth.c
===================================================================
--- kernel/forth.c	(revision 1395)
+++ kernel/forth.c	(working copy)
@@ -1848,6 +1848,26 @@
    PUSH(rstack[rstackcnt - 2]);
 }
+/*
+ *  fprintk  ( addr len -- )
+ *  writes a forth string to the serial output
+ */
+
+static void fprintk(void)
+{       
+    int len = POP();
+    int addr = POP();
+    char *message = malloc(sizeof(char) * 5000);
+    snprintf(message, len + 1, "%s", addr);
+    int i;
+    for (i = 0; i < len; i++) {
+        if (message[i] == '\r')
+            message[i] = ' ';
+    }
+    printk(message);
+    free(message);
+}
+
 /* words[] is a function array of all native code functions used by
  * the dictionary, i.e. CFAs and primitives.
  * Any change here needs a matching change in the primitive word's
@@ -1963,4 +1983,5 @@
     do_encode_file,         /* $encode-file */
     do_debug_xt,            /* (debug  */
     do_debug_off,           /* (debug-off) */
+    fprintk,                /* fprintk  */
 };
Index: libc/extra.c
===================================================================
--- libc/extra.c	(revision 1395)
+++ libc/extra.c	(working copy)
@@ -31,7 +31,7 @@
int forth_printf( const char *fmt, ... )
 {
-	char buf[512];
+	char buf[5000];
    va_list args;
    int i;
Well after trying to run Mac OS 9.2 several times, this was the output:
['] display-ih cell+['] frame-buffer-adr cell+['] openbios-video-width cell+['] openbios-video-height cell+['] depth-bits cell+['] line-bytes cell+['] color-palette cell+to fb8-blitmaskto fb8-fillrectto fb8-invertrectto (romfont)to (romfont-height)to (romfont-width)['] vga-driver-fcode 2 cells + 1 byte-load: write dup >r bounds do i c@ fb-emit loop r> ; : draw-logo draw-logo ; : restore reset-screen ; fcode-debug?
...
...
=============================================================
OpenBIOS 1.1 [May 2 2016 02:45]
Configuration device id QEMU version 1 machine id 1
CPUs: 1
Memory: 384M
UUID: 00000000-0000-0000-0000-000000000000
CPU type PowerPC,750
milliseconds isn't unique.
...
...
bootstrdup encode-string " selected-partition-args" propertystrdup encode-string " selected-partition-args" propertyload-baseload-baseload-baseload-size here >r dev / " model" active-package get-package-property abort" can't find MODEL" decode-string 2swap 2drop " iMac,1" $= ?dup 0= if  " compatible" active-package get-package-property abort" can't find COMPATIBLE"  false >r  begin   dup while   decode-string here over 2swap bounds ?do    i c@ dup [char] A [char] Z between if h# 20 xor then c,    loop   2dup " macrisc" $= r> or >r   2drop   repeat  2drop r>   then r> here - allot 0= abort" this image is not for this platform" decimal 1 load-base load-size 14 - adler32    load-base load-size + 12 - 12 ['] eval catch if  2drop ." , bad checksum value" -1   then  <> if  ." , checksum error"  abort   then hex dev /openprom 0 0 " supports-bootinfo" property  device-end " /chosen" find-package 0= abort" can't find '/chosen'" constant /chosen " memory" /chosen get-package-property abort" memory??" decode-int constant xmem 2drop " mmu" /chosen get-package-property abort" mmu??" decode-int constant xmmu 2drop " AAPL,debug" " /" find-package 0= abort" can't find '/'"
I don't know if I can trust this output because there appears to be a limit to how much can be printed to the serial console. Sometimes I would see at the end "h# C864630D". I'm not sure why. This text is located at the very end of the boot script file. Past the forth section. I don't think the abort" word is the problem because there is no indication that it aborted the script. Hopefully someone will find this information useful.

    