~maddie/custom-processor-specification

7473adafeb4f0a424c7bd2acb1dee869cd164e0c — Madeline Cronin 3 months ago 7195b77
Remove the 512 word copy behaviour and change references to RAM
The removal is because the copy behaviour would be better placed in a platform architecture
the references to RAM are changed to be "main memory" so that a platform architecture can use different
blocks of main memory for different purposes.
1 files changed, 3 insertions(+), 4 deletions(-)

M ISA_spec.txt
M ISA_spec.txt => ISA_spec.txt +3 -4
@@ 1,4 1,4 @@
Maddie's test ISA Version 1.0.2
Maddie's test ISA Version 1.0.3


Table of contents:


@@ 22,8 22,7 @@ counter, and interrupt register. The program counter is freely readable, but
only modifiable through instructions in the control flow category. There is
also a 2 bit flags register for storing the condition flags.

Behaviours: Upon power up, the first 512 words of disk are copied to main
memory. The only statefulness not directly controlled by programs is the
Behaviours: The only statefulness not directly controlled by programs is the
interrupt toggle. Numbers are read as big endian. Hardware interrupts jump to
zero, and push the prior program counter to the stack.



@@ 121,7 120,7 @@ A: (A=0) Read/pop, (A=1) Write/push

XXX=
000: Pop/push to stack
001: Read/write RAM
001: Read/write main memory
010: R/W disk
011: R/W VRAM
100: R/W to serial port