Piston X86-64 Assembler

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Author: Tommi Pisto, Version: 0.0.1

About Piston Assembler

Piston X86-64 Assembler (PASM) is NASM syntax based symbolic machine code compiler for X86-64 architecture - fully working in browser and in Node.js based environments.

Written in CoffeeScript (and compiled to JavaScript) during the rainy finnish summer holiday.

Current Features

X86-64 opcodes
NASM syntax
16,32,64 bit modes
R8-R13 registers
SIB, MODR/M, RIP addressing
EQU, TIMES
labels, expressions
testing framework
...

Thanks to

Karel Lejska, x86reference.xml, x86asm.net
Kenneth Falck, ASM code for testing
Vikas N. Kumar, ASM code for testing
Joni Salonen, toUTF8Array
Zachary Carter, Jison
John Tobey and Matthew Crumley, Javascript-biginteger
Jeremy Ashkenas, CoffeeScript

REAL-TIME Compiling

Sleek. Fast. Clean. Responsive. Line by line opcode explanation.

Prefix

REX prefix Byte

REX				W	R	X	B
0	1	0	0	0	0	0	0

Opcode

modRM Byte

mod

reg

r/m

SIB Byte

scale

index

base

Immediate

Displacement

Relative address

X86-64 ASM code

; NASM MBR boot loader
[bits 16]                               ; 16-bit code
[org 0x7c00]                            ; BIOS loads us at 0x07c0:0000
jmp 0x0000:initialize_bios              ; reset code segment to 0x0000 with long jump

initialize_bios:
        xor ax, ax
        mov ds, ax                      ; reset data segments to 0x0000
        mov es, ax
        mov [bootdrive], dl             ; store boot drive
        mov si, welcome                 ; print welcome string
        call print
        ;jmp load_kernel_header         ; proceed to load kernel

halt:
        hlt                             ; halt CPU to save power
        jmp halt                        ; loop if halt interrupted

print:                                  ; Print string in SI with bios
        mov al, [si]
        inc si
        or al, al
        jz exit_function                ; end at NUL
        mov ah, 0x0e                    ; op 0x0e
        mov bh, 0x00                    ; page number
        mov bl, 0x07                    ; color
        int 0x10                        ; INT 10 - BIOS print char
        jmp print
        exit_function:
        ret

data:
        welcome db 'Loading...', 0      ; welcome message
        error db 'Error', 0             ; error message
        bootdrive db 0x00               ; original BIOS boot drive

times 200 - ($ - $$) db 0               ; should fill to 510 bytes. For demo changed to 200 bytes.
dw 0xaa55                               ; boot signature (fills to 512 bytes)
                                        ;
                                        ; Bootloader by Kenneth Falck

PASM

World's first X86-64 (AMD64) Assembler
written in JavaScript!

Works fully in modern web browsers

about

About Piston Assembler

Current Features

Thanks to

REAL-TIME Compiling

X86-64 ASM code

Compiled bytecode

PASM

World's first X86-64 (AMD64) Assembler written in JavaScript! Works fully in modern web browsers

about

About Piston Assembler

Current Features

Thanks to

REAL-TIME Compiling

X86-64 ASM code Clear

Compiled bytecode

World's first X86-64 (AMD64) Assembler
written in JavaScript!

Works fully in modern web browsers

X86-64 ASM code