Software CPU emulator

This is a simple "CPU emulator", which consists of the following components:

1. Assembler [asm+.exe] - translates assembly (.asy) programs into bytecode (.bsy) "executable" files.
2. Disassembler [asm-.exe] - translates back bytecode into assembly.
3. CPU emulator [scpu.exe] - runs bytecode programs.

Assembly syntax

These are all the commands that are supported:

Input

• in
• out

Arithmetic

• add
• sub
• mul
• div

Math

• pow
• sqrt
• sin
• cos
• abs
• flr

Stack

• push
• pop

Control flow

• call
• ret
• jmp
• jae
• ja
• jb
• jbe
• je
• jne
• hlt

Graphics

• upd
• clr

Example 1 - factorial

; number of which to take the factorial
in

; calling fact function, after its execution the answer will be on top of the stack
call :fact
out

hlt

fact:
	pop rax
	push 1
	call :fact_rec

	ret

fact_rec:
	push rax
	mul

	push rax
	push 1
	sub

	pop rax

	push 1
	push rax

	jae :end
		call :fact_rec

	end:
		ret

Example 2 - quadratic equation

; input a, b, c coefficients of a quadratic equation (ax^2 + bx + c = 0)
in
in
in

call :sqeq
hlt

; solves square equation
; takes three coefficients from stack
sqeq:
	pop rcx
	pop rbx
	pop rax

	; if rax == 0 solve linear
	push rax
	push 0
	je :lineq

	; if rax != 0 solve square
	jmp :square

; solves linear equation
lineq:
	push rcx
	
	push rbx
	push -1
	mul

	div

	out

	ret

; solves square equation in case rax != 0
square:
	push rbx
	push rbx
	mul

	push 4
	push rax
	push rcx
	mul
	mul

	sub

	pop rdx

	push rdx
	push 0
	ja :twosols

    push rdx
    push 0
	je :onesol

    jmp :nosol

	twosols:
        push 2
        out

        push rdx
		sqrt
		pop rdx

		push rbx
		push -1
		mul
		push rdx
		add
		push 2
		div
		out

		push rbx
		push -1
		mul
		push rdx
		sub
		push 2
		div
		out

		ret

	onesol:
        push 1
        out

		push rbx
		push -1
		mul

		push 2
		push rax
		mul

		div

		out

		ret

    nosol:
        push 0
        out

Example 3 - basic wireframe renderer of a 3d cube

this and the previous examples can be found in the examples/ folder

Libraries used

1. SDL2
2. (my) file_manager
3. (my) stack
4. (my) log_generator