siraerown / hoos

An assembly language

Hoos Assembly language

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The Hoos assembly language features syntax similar to intel assembly, it runs with a python interpreter. Hoos is turing complete. It has memory restrictions on both the main memory and the stack, these are arbitrary and can easily be increased by editing the interpreter. The number of registers is also arbitrary and can be increased on a whim.

Interpreter Usage

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The interpreter can take 1, 2 or 4 arguments. The default is to pass one argument: the filename of the .hoo file to be run.

$ python interpreter.py wa.hoo

The second option is to pass two arguments which causes the interpreter to compile the .hoo file into a out.py file which can be run with python.

$ python interpreter.py -c wa.hoo
$ python out.py

The last option is to pass four arguments which causes the interpreter to compile the .hoo file into a file with the name of the last argument

$ python interpreter.py -c wa.hoo -o cav.py
$ python cav.py

Language Definition

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Instructions:

Instruction	Description
pop a	a = stack[rsp]; decrementing rsp is up to program
push a	stack[rsp+1] = a; incrementing rsp is up to program
add a, b, c	a = b + c
sub a, b, c	a = b - c
xor a, b, c	a = b xor c
or a, b, c	a = b or c
and a, b, c	a = b and c
not a, b	a = not b
shiftr a, b, c	a = b shifted c bits right
shiftl a, b, c	a = b shifted c bits left
nop	does nothing
jmp a	jump to instruction a
jmpe a, b, c	jump to instruction a if b == c
jmpl a, b, c	jump to instruction a if b < c
jmpg a, b, c	jump to instruction a if b < c
inc a	a += 1
dec a	a -= 1
mov a, b	a = b
print a, b	if b == 0, prints int value of a, else prints ascii value of a
read a	reads in single character or entire int
halt	stops execution
call a	pushes PC onto stack and jumps to a
ret	pops top of stack into PC and jumps to PC
var name a	puts value a into memory, accessible with name, address accessible with [name], name can only be letters and cannot be the same as a register name
debug	dumps memory and registers
label:	label style is "name:"

Arguments

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Arguments to instructions follow the general pattern instruction <destination>, <source1>, <source2> The destination cannot be a constant value, doing so will result in a runtime error.

Constants

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There are 5 different ways to represent a constant in your code:

Representation	Type
0b1101	Two's compliment binary, must be prefixed with 0b
0xabad1dea	Two's compliment hex, must be prefixed with 0x
0d123	Decimal, prefixed with 0d
123	Decimal, no prefix
'a'	Char, must be within ''

Registers:

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Refister	Description
r0-r15	regular registers
rsp	stack pointer, supposed to point at top USED slot of stack
rbp	base pointer
rax	return value for functions, accumulator
PC	Program Counter, points to next instruction, that is, what will be executed next, should not be modified directly

Calling Convention

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r10-r15used as first 6 parameters, any others must be put on stack. Any other registers used in function must be backed up and then restored from stack.

Memory

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Main memory is 2^16 slots of python ints. Stack is 2^8 slots of python ints. The number of labels is not explicitly limited. The number of variables is limited by the the space in memory.