Semi-functioning Intel 8080 assembler and emulator.
<EXE> [<file-path>] - Assemble and run the file at <file-path>. If no file path is specified, run an empty emulator instance.
Example programs are provided under ./examples.
Currently supports all standard instructions and data statements, as well as some pseudo-instructions (see below). Input/output instructions use stdin/stdout (see below). Hardware interrupts are not supported.
The stack pointer defaults to the value 0, which means that any PUSH instruction will cause a stack overflow error. Thus, it is recommended to set the stack pointer register at the start of the program, for example by using the LXI instruction (LXI SP, 0FFFFH).
Label names may be 1-5 characters long, and can contain any capital alphabetical or numerical characters, except for the first character, which may be a capital alphabetical character or any of the characters @ and ?. Examples:
Valid label names: @MAIN, ?JUMP, ABCDE, S1234, @, ABC
Invalid label names: 12345, ABCDEFGH, A@, ?JMP?, main, ?jump, T_AB, ``
Numerical values can be specified in decimal, octal or hexadecimal format by appending a base-dependent character to the digit string:
- Decimal: no character (
12345) - Hexadecimal:
H(0FFFFH) - Octal:
OorQ(17Q)
It is recommended to prefix all hexadecimal numerical values with 0 to ensure that they are not parsed as labels.
For a complete list of all available instructions, see the Intel 8080 documentation / programmers's guide. Instruction arguments may only be provided in the form of register names, constant values (in decimal/octal/hexadecimal) or, where applicable, labels. The instruction format is otherwise as specified in the Intel 8080 documentation.
The input/output device number specified in the instruction is mapped as follows:
IN 0: Reads one byte from stdin, and stores it in the accumulator register.
IN 1: Set the accumulator register to a random value in the range 0-255.
IN x for all other x: Sets the accumulator register to 0.
OUT 0: Writes the byte stored in the accumulator register to stdout.
OUT 1: Writes the byte stored in the accumulator register to stdout formatted as a decimal number.
OUT 2: Writes the word stored in the HL register pair to stdout formatted as a decimal number.
OUT x for all other x: No-op.
Data statements define data to be stored at a specified memory location.
The provided argument may be either a numerical constant or a single quote-enclosed string constant. Examples:
DB 012H: Stores the value 0x12 at the address of the statement.
DB 'Hello, world!': Stores the given string in a section of bytes starting at the address of the statement, encoded in ASCII.
The provided argument may be either a numerical constant or the name of a label. Examples:
DW 12345: Stores the value 12345 in the two-byte sequence starting at the address of the statement.
DW LABEL: Stores the address of the label LABEL in the two-byte sequence starting at the address of the statement.
The provided argument must be a numerical constant, specifying the size, in bytes, of the storage section. Example:
DS 100Q: Allocates a section of size 0o100 as data storage, starting at the address of the statement.
Determines the program's starting address. May only be put at the start of the program. Example:
ORG 0100H: Shifts all instructions' and data statements' addresses by the number 0x100.
Must appear at the very end of the program, and may not appear more than once. Signifies the end of the program.
The following pseudo-instructions documented in the Intel 8080 specification are not currently supported:
EQU, SET, IF, ENDIF, MACRO, ENDM