CAR/README.md

Cool ARM Ripoff

A simple (and ridiculous) virtual machine/CPU made for no real reason/purpose.

Written in C, made by David Goeke.

Current features:

• few to none.
• 32 general purpose registers
• 32-bit addresses

Needed features:

• conditional jmps

Instuctions (arithmetic):

• add
• sub (subtract)
• mul (multiply)
• div (divide)
• mod (modulus, division remainder)
• shl (logical shift left)
• shr (logical shift right)
• ahr (arithmetic shift right)
• ror (logical rotate right)
• and (logical AND)
• or (logical OR)
• xor (logical XOR)
• not (logical NOT/invertion)
• xchg (exchange registers)
• fp_add (add floating point values in registers)
• fp_sub (subtract floating point values in registers)
• fp_mul (multiply floating point values in registers)
• fp_div (divide floating point values in registers)
• fp_mod (modulus (division remainder) floating point values in registers)

Insutrctions (load/store):

• ldr (load register with value from memory, using the program counter as the base)
• lds (load register with value from memory, using the stack pointer as the base)
• ldb (load register with value from memory, using a specified register as the base)
• ldi (load register with and immediate value, only low 21 bits)
• str (store register at memory, using the program counter as the base)
• sts (store register at memory, using the stack pointer as the base)
• stb (store register at memory, using the specified register as the base)
• ldh (load high 11 bits of register with immediate)
• sti (store a 21-bit immediate at memory, using the program counter as the base)
• stj (store a 21-bit immediate at memory, using the stack pointer as the base)
• push (push register onto stack)
• pushi (push 21-bit immediate onto stack)
• pop (pop value from stack into register)
• sth (stroe high 11 bits of register to memory, using pc as the base)
• stk (stroe high 11 bits of register to memory, using sp as the base)

Instructions (misc):

• nop (do nothing)
• call (call subroutine/function)
• ret (return from subroutine/function)
• jmp (jump to memory address)