Thursday, 2 January 2014

Now working......

Well, partly. The TMS1100 emulator is up and running and seems to be working okay, and you can control it from the keyboard - set breakpoints, single step and so on.

It has been running this code.

ldx 0
tcy 0 // point to start
imac // increment and load digit
tam // write it back
ac6ac // add 6
br carryout // if carry set, then carry out
br nextdigit // else start again.
cla // clear the current one
iyc // increment Y
cla // in case of carry out, unlikely !
br carryforward

All this does is increment each memory location one at a time till 10, carrying forwards, so it works like a giant counter with one digit in each memory location.

The point of this is to speed test (alternatively, to check it runs at the right speed). On my machine it was executing about 0.96 million loops a second, which equates to about 6.4Mhz clock speed (on the TMS series 1 instruction = 1 clock cycle*) . The TMS1100 runs at 50Khz or so, so it's going to be quick enough :)

It doesn't emulate any of the other hardware - LCD, Keyboard and Speaker (I'm not going to code for the rotary controller) - yet.

* note: for the pedantic, the clock speed is six times this, and it runs at 300Khz, every instruction being 6 clock cycles in length.

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