[OpenBIOS] Implementing a second return stack

Programmingkid programmingkidx at gmail.com
Sun Apr 17 04:11:36 CEST 2016

Mac OS 9 does alter the return stack in OpenBIOS. This is perceived to be unacceptable. The solution to this issue has been stated as implementing a second return stack. This stack would just be an array that implements push and pull calls. 

In the bootinfo_load.c file, in the bootinfo_init_program() function is where the Mac OS 9 boot script is read into memory, into the bootscript variable. What I want to do is replace all >r and r> calls in the bootscript buffer with other words. Something like substitute>r and substitute_r>. These words would use a separate array to push and pop data from. I think this would work because Mac OS 9's boot script only uses the return stack for data storage. Does this sound like the right thing to do?

More information about the OpenBIOS mailing list