Failure to persist user/drive state

[skx]

[I have a patch ready for this, which I will submit shortly]

When I was writing my emulator I wrote some test programs to cement my understanding of some of the expected behaviour. One simple script I wrote was ret.z80, which is a trivial binary which just tries to exit in a couple of different ways:

• JP 0x0000
• RST 0
• RET
• LD C, 0x00; CALL 0x0005

There is a binary which is located within that same directory which can be used for testing - but note that you really want to map this to a non-default drive. In my case I see this when I test:

$ ./target/debug/iz-cpm --disk-a /home/skx/Repos/github.com/skx/cpm-dist/A/ --disk-b  /home/skx/Repos/github.com/skx/cpmulator/samples/ 
iz-cpm https://github.com/ivanizag/iz-cpm
CP/M 2.2 Emulation
Press ctrl-c ctrl-c Y to return to host

A>b:
B>dir ret.*
RET     .COM  |  RET     .Z80
B>ret 1

B>ret 2

B>ret 3

B>ret 4

A>

Here you see that the execution of the binary succeeded in each of the invokations, each time the binary was launched and then terminated. However The last run switched back to the default A-drive.

You correctly pass this value along when reseting via the boot:

                      let user_drive = machine.peek(CCP_USER_DRIVE_ADDRESS);
                    cpu.registers().set8(Reg8::C, user_drive);

However that value is never set. I've made a couple of other changes to remove the "= 0" from the drive/user setting in the rest/state, and added the missing stores.

That allows things to work as expected.

[ivanizag]

Wow. I just wrote a comment on the other one :D

[ivanizag]

Great if you have a patch. Thanks

[skx]

No burden, I have an hour just now and I'll write up the things that jumped out at me.

Probably no patches for the others though, at least not tonight! (And I appreciate some things might be a matter of interpretation so I'm happy for you to close any report I make as "Won't fix :)" )