Lasm

LASM

What is LASM?

LASM (Lua Assembly), is a low-level programming language created by User: Alx was designed to be used for a Lua/Python compiler, for an abandoned and unnamed project which compiled Lua to LASM (and assembled into LASM bytecode).

LASM VM

The LASM VM is a register machine, which also utilizes a stack incase register operations are not safe, otherwise register operations are preferred. The LASM VM has 3 registers, being A, B and C.

LASM Instruction Specifications

LASM Instruction Format

The LASM instruction size is a fixed 4 bytes / 32 bits long, with the exception of two instructions, which both have unsigned longs as as operand.

The LASM instruction layout specification is as follows:

Instruction Type A

First Bit (0)
   Opmode: 8 bits
Operand A: 8 Bits
Operand B: 8 bits
   Opcode: 8 bits
Last Bit (32)

Instruction Type B

First Bit (0)
         Opmode: 8 bits
      Operand A: 8 Bits
      Operand B: 8 bits
         Opcode: 8 bits
Extened Operand: 32 bits
Last Bit (64)

The opmode specification specifies if the operands are immediate values, or register values. The opmode pairing specification is as follows:

OPMODE A SPEC	OPMODE B SPEC	VALUE (base16)
REGISTER	REGISTER	0x11
REGISTER	IMMEDIATE	0x10
IMMEDIATE	REGISTER	0x01
IMMEDIATE	IMMEDIATE	0x00

LASM Instruction Set

The following table contains the entire LASM instruction set.

Legend: ... -> N/A

Opcode	Operand A	Operand B	Opmode	Description
ADD_R	uint8_t	uint8_t	...	Add two registers, store result in first register.
ADD_S	...	...	...	Pop two items off the stack, perform addition and push back to stack.
AND_S	...	...	...	Pop two items off the stack, perform a logical AND, push back to stack.
BOR_S	...	...	...	Pop two items off the stack, perform a logical OR and push back to stack.
CMP	uint8_t	...	...	Pop two items off the stack, perform one of the following: (==, ~=, <=, >=, <, >) and push result to stack.
CMP_R	uint8_t	uint8_t	...	Obselete opcode.
FASTCALL	uint8_t	...	...	The first calling convention, which will use registers as the arguments for the function call. (Max argc: 3)
IMPORT	uint8_t	...	...	Obselete opcode.
JMP_ULONG	uint8_t	uint32_t	...	Absolute long jump.
JMP_ULONG_FALSE	uint8_t	uint32_t	...	Conditional long jump.
MMUL_R	uint8_t	uint8_t	...	Obselete opcode.
MMUL_S	...	...	...	Obselete opcode.
MOD_R	uint8_t	uint8_t	...	Perform modulo on two registers, store result in first register.
MOD_S	...	...	...	Pop two items off the stack, perform modulo and push back to stack.
MOV	uint8_t	uint8_t	...	Move either a register into a register, or an immediate value into a register.
MOVG_A	uint8_t	...	...	Move a global (first operand pointing to the global name in the constants pool) into register A.
MOVG_B	uint8_t	...	...	Move a global (first operand pointing to the global name in the constants pool) into register B.
MOVG_C	uint8_t	...	...	Move a global (first operand pointing to the global name in the constants pool) into register C.
MOVK_A	uint8_t	...	...	Move a constant value (first operand pointing to the constant in the constant pool) into register A.
MOVK_B	uint8_t	...	...	Move a constant value (first operand pointing to the constant in the constant pool) into register B.
MOVK_C	uint8_t	...	...	Move a constant value (first operand pointing to the constant in the constant pool) into register C.
MUL_R	uint8_t	uint8_t	...	Perform multiplication on two registers, store result in first register.
MUL_S	...	...	...	Pop two items off the stack, perform multiplication and push back to stack.
POP	uint8_t	...	...	Pop the topmost stack item into a register.
POW_R	uint8_t	uint8_t	...	Perform exponentiation on two registers, store result in first register.
POW_S	...	...	...	Pop two items off the stack, perform exponentiation and push back to stack.
PUSH_G	uint8_t	...	...	Push a global to the stack.
PUSH_K	uint8_t	...	...	Push a constant to the stack.
PUSH_R	uint8_t	...	...	Push register contents to the stack.
STDCALL	uint8_t	...	...	The second calling convention, where the arguments are on the stack, rather than registers.
SUB_R	uint8_t	uint8_t	...	Perform subtraction on two registers, store result in first register.
SUB_S	...	...	...	Pop two items off the stack, perform subtraction and push back to stack.
XOR_S	...	...	...	Pop two items off the stack, perform a bitwise XOR and push back to stack.
NOT	...	...	...	Performs a logical NOT on the topmost stack item.
RET	...	...	...	Jump to offset stored in register C. Used for non-nested custom function calls.
STORE_R	uint8_t	uint8_t	...	Store register contents in a global pointed to by operand A.
STORE_S	uint8_t	...	...	Pop an item off the stack, and store it in a global pointed to by operand A.
JMP_INC	uint8_t	...	...	Incremental short absolute jump.
JMP_INC_FALSE	uint8_t	...	...	Incremental short conditional jump.
DISCARD	...	...	...	Pop the topmost stack item off the stack.
JMP_UCHAR	uint8_t	...	...	Stores current offset in register C, and short absolute jumps to offset in operand A.
GETATTR_R	uint8_t	uint8_t	...	Obselete opcode.
JMP_DEC	uint8_t	...	...	Decremental absolute jump.
JMP_UCHAR_T	uint8_t	...	...	Short absolute jumps to offset in operand A. Does not store previous offset.
PUSH_LL	uint8_t	...	...	Obselete opcode.
MOVLL_A	uint8_t	...	...	Obselete opcode.
MOVLL_B	uint8_t	...	...	Obselete opcode.
MOVLL_C	uint8_t	...	...	Obselete opcode.

LASM Language Rules

LASM follows the simple language layout.

(opcode) [operand], [operand] [$opmode]

LASM Example programs

1. Hello World

; constant indexes in constants pool
#const __PyGbl_print = 0
#const __Py_hello_world = 1

jmp_uchar main

main:
 push_g __PyGbl_print $KK
 movk_a __Py_hello_world $KK
 fastcall 1 $KK

Extra

I may expand this.