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TIS-100 Game Notes / Subroutines
12 Feb 2019I’ve been playing TIS-100, which is a puzzle programming game. It consists of interconnected nodes that have a single register (ACC) and one backup register (swappable-only, BAK). Each node is programmed individually and can communicate with each other through MOV instructions. They are all granted a subset of assembly:
# ADDRESSABLES
<SRC/DST> = LEFT, RIGHT, UP, DOWN the node in that direction
<SRC/DST> = ANY any connected node
<SRC/DST> = LAST the last node used by ANY
<SRC/DST> = ACC this node's ACC register
MOV <SRC>, <DST> sends SRC => DST
# ARITHMETIC
SUB <SRC> sets ACC => ACC-SRC
ADD <SRC> sets ACC => ACC+SRC
NEG sets ACC => -ACC
# REGISTERS
SAV - sets registers BAK=>ACC
SWP - swaps registers BAK<=>ACC
# GOTOS
<LABEL> = a "goto" line marker, eg: "START:"
JMP/JEZ/JGZ/JLZ <LABEL> - jump based upon ACC being any/equal-to-zero/greater-than-zero/less-than-zero
JRO <SRC> - jump to an offset from current line, eg -1 will jump to previous instruction, 1 will jump to next instruction
During the game you are forced to create subroutines inside each node, since each node can only hold 15 lines of instructions. You must essentially call each subroutine by using the MOV instruction to pass messages between nodes.
I wanted to note down the subroutines as I create them in the game for my own use as well as anyone else that is interested.
CMP Subroutine
Takes in two arguments (a, b) from source and compares them.
- If a is larger than b, return 1
- If a is equal to b, return 0
- If a is less than b, return -1
START:
MOV ANY, ACC # A
SUB LAST # B
JEZ EQUAL
JLZ LESS
MOV 1, LAST # A>B
JMP START
EQUAL:
MOV 0, LAST # A=B
JMP START
LESS:
MOV -1, LAST # A<B
ABS Subroutine
Takes in a single argument, returns the absolute value of the argument.
START:
MOV ANY, ACC
JLZ NEG
MOV ACC, LAST
JMP START
NEG:
NEG
MOV ACC, LAST
DELTA Subroutine
Takes in two arguments, returns the delta between the two arguments.
MOV ANY, ACC
SUB LAST
MOV ACC, <ABS_NODE>
MOV <ABS_NODE>, LAST
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