TCPU

Machine code interpreter written in pure C. Can execute programs up to 1 MEGABYTE (1048576 bytes) in size!!!

Building

1. Install cbuild
2. Install SDL3 and SDL3_image from package manager or source.

3. cbuild build_exec_dbg
   

Assembly language

Instructions

code	name	arguments	details
00	NOP		ignored instruction
01	MOVC	dst_register, value	push constant value into dst_register
02	MOVR	dst_register, src_register	copy value from src_register to dst_register
03	ADD	dst_register, src_register	dst += src
04	SUB	dst_register, src_register	dst -= src
05	MUL	dst_register, src_register	dst *= src
06	DIV	dst_register, src_register	dst /= src
07	MOD	dst_register, src_register	dst %= src
08	SYS		call system function
09	EXIT		stop the program with exit code in ax

Registers

code	name	size (bits)
01	ax	32
02	bx	32
03	cx	32
04	dx	32

System functions

To call a system function you need to push values to registers and write SYS opcode. The return value of a function will will be avaliable in ax after call.

ax	name	bx	cx	dx	details
0	read	file number	buffer pointer	buffer size	read data from file
1	write	file number	buffer pointer	buffer size	write data to file