A Python based 8085 assembler.
To clone this repository and assemble the demo file, open a terminal and run:
git clone https://github.com/ept221/8085-Assembler.git
cd 8085-Assembler/src/
python3 assembler.py demo.asm -susage: assembler.py [-h] [-L] [-A] [-B] [-I] [-H] [-C] [-c] [-s] [-b] [-o OUT] source
A simple 8085 assembler.
positional arguments:
source source file
options:
-h, --help show this help message and exit
-L, --lineNum include the line number in output
-A, --address include the address in output
-B, --label include the labels in output
-I, --instruction include the instructions and arguments in output
-H, --hex include the hex code in output
-C, --comment include the comments in output
-c, --compressed don't include empty segments in output
-s, --standard equivalent to -A -B -I -H -C -c
-b, --binary output code as binary file (can only be combined with -o)
-o OUT, --out OUT output file name (if not specified: stdout, unless -b used, then: "out.bin")
Comments begin with semicolons.
MVI A, 0x5C ; This is a commentConstants are in decimal by default, but hexadecimal and binary are also supported. Constants can also be negative and are stored in two's complement form when assembled. They can also be characters.
MVI A, 10 ; Decimal constant
MVI A, 0x0A ; Hexadecimal constant
MVI A, 0b1010 ; Binary constant
MVI A, -10 ; Negative constant
MVI A, 'a' ; A character constant
MVI A, '\n' ; A character escape sequence constant
; Retro formats:
MVI A, 0AH ; Hexadecimal constant
MVI A, #12 ; Hexadecimal constant
MVI A, $12 ; Hexadecimal constantLabel definitions may be any string ending with a colon, where the string does not match the pattern of a constant.
; Example
;*******************************************************************************
MVI A, 0x5C
Foo: DCR A ; Label definition
JNZ Foo ; Jump-not-zero to Foo
;*******************************************************************************
MVI A, 0x5C
0xFD: DCR A ; Illegal. Label definition cannot match hex constant format
JNZ 0xFDSome unofficial instructions such as SHLD are supported, and are allowed to be surrounded by parentheses:
; Example
;*******************************************************************************
(SHLD) 0x76
;*******************************************************************************
Address Label Instruction Hex Code
--------------------------------------------------------------------------------
0x0000 SHLD 0x76 0x22
0x0001 0x76
0x0002 0x00 Sets the origin to the given address. Only forward movement of the origin is permitted.
; Example
;*******************************************************************************
MVI A, 0x55
OUT 0x42
JMP Start
Start: ORG 0x44
MVI A, 0x32
OUT 0x42
;*******************************************************************************
; Assembles to the following:
; (shown in compressed mode, where empty segment isn't displayed)
Address Label Instruction Hex Code
--------------------------------------------------------------------------------
0x0000 MVI A, 0x55 0x3E
0x0001 0x55
0x0002 OUT 0x42 0xD3
0x0003 0x42
0x0004 JMP Start 0xC3
0x0005 0x44
0x0006 0x00
0x0044 Start: MVI A, 0x32 0x3E
0x0045 0x32
0x0046 OUT 0x42 0xD3
0x0047 0x42 ; Example
;*******************************************************************************
ORG 0x44
MVI A, 0xC7
OUT 0x44
ORG 0x00 ; Illegal. Cannot move origin backwards
JMP 0x0044Writes one or more data bytes sequentially into memory.
; Example
;***********************************************************
MVI A, 33
DB 0x44, 0xFE, 0x9C
HLT
;***********************************************************
; Assembles to the following:
Address Instruction Hex Code
------------------------------------------------------------
0x0000 MVI A, 33 0x3E
0x0001 0x33
0x0002 DB 0x44
0x0003 DB 0xFE
0x0004 DB 0x9C
0x0005 HLT 0x76 Writes one or more data word sequentially into memory.
; Example
;***********************************************************
MVI A, 33
DW 0xDEAD, 0xBEEF
HLT
;***********************************************************
; Assembles to the following:
Address Instruction Hex Code
------------------------------------------------------------
0x0000 MVI A, 33 0x3E
0x0001 0x21
0x0002 DW 0xAD
0x0003 DW 0xDE
0x0004 DW 0xEF
0x0005 DW 0xBE
0x0006 HLT 0x76 Equates a symbol with a number.
; Example
;***********************************************************
foo EQU 0xC5F3
MVI A, 0x33
LXI H, foo
;***********************************************************
; Assembles to the following:
Address Instruction Hex Code
------------------------------------------------------------
0x0000 MVI A, 0x33 0x3E
0x0001 0x33
0x0002 LXI H, foo 0x21
0x0003 0xF3
0x0004 0xC5 Defines and reserves the next n-bytes for storage.
; Example
;*******************************************************************************
JMP END
Storage: DS 0x05
LDA Storage
END: OUT 0x42
;*******************************************************************************
; Assembles to the following:
; (shown in compressed mode, where empty segment isn't displayed)
Address Label Instruction Hex Code
--------------------------------------------------------------------------------
0x0000 JMP END 0xC3
0x0001 0x0B
0x0002 0x00
0x0008 STORAGE: LDA STORAGE 0x3A
0x0009 0x03
0x000A 0x00
0x000B END: OUT 0x42 0xD3
0x000C 0x42 Writes an ASCII string into memory. Double quotes and backslashes must be escaped with a backslash. The string is not null terminated by default, but can be terminated by adding \0 to the string.
; Example
;*******************************************************************************
STRING "The robot says \"Hi!\"\0"
;*******************************************************************************
; Assembles to the following:
Address Instruction Hex Code
------------------------------------------------------------
0x0000 STRING 0x54
0x0001 STRING 0x68
0x0002 STRING 0x65
0x0003 STRING 0x20
0x0004 STRING 0x72
0x0005 STRING 0x6F
0x0006 STRING 0x62
0x0007 STRING 0x6F
0x0008 STRING 0x74
0x0009 STRING 0x20
0x000A STRING 0x73
0x000B STRING 0x61
0x000C STRING 0x79
0x000D STRING 0x73
0x000E STRING 0x20
0x000F STRING 0x22
0x0010 STRING 0x48
0x0011 STRING 0x69
0x0012 STRING 0x21
0x0013 STRING 0x22
0x0014 STRING 0x00 Anytime an instruction or directive requires a numerical argument, an expression can be used. Supported operations inside expressions include addition and subtraction. The location counter $ is also made available. Expressions may contain symbols, but must resolve within two passes of the assembler, and if used for directive arguments, must resolve in a single pass. All expressions must evaluate to a positive number.
; Example with expression resolution in one pass.
;***********************************************************
foo EQU 0x10
MVI A, foo - 0x04
;***********************************************************
; Assembles to the following:
Address Instruction Hex Code
------------------------------------------------------------
0x0000 MVI A, foo - 0x04 0x3E
0x0001 0x0C
; Example with expression resolution in two passes.
;***********************************************************
MVI A, foo + 0x04
foo EQU 0x30
;***********************************************************
; Assembles to the following:
Address Instruction Hex Code
------------------------------------------------------------
0x0000 MVI A, foo + 0x04 0x3E
0x0001 0x34; Example with expression resolution in two passes, and $
;***********************************************************
MVI A, 0x55
JMP $ + foo
foo equ 0x05
DB $, $ + 0x01, $ + foo
DS 02
HLT
;***********************************************************
; Assembles to the following:
; (shown in compressed mode, where empty segment isn't displayed)
Address Instruction Hex Code
------------------------------------------------------------
0x0000 MVI A, 0x55 0x3E
0x0001 0x55
0x0002 JMP $ + foo 0xC3
0x0003 0x07
0x0004 0x00
0x0005 DB 0x05
0x0006 DB 0x07
0x0007 DB 0x0C
0x000A HLT 0x76