Assembler for the CYY VM

The assembler for the CYY-VM ist called cyysam.

Each source file consists up to three sections:

.DATA

Contains all definitions of constant values.

.BSS

Contains all definitions of variables.

.TEXT

Contains the program code

Here is a table with all supported instructions.

Example

Example of an recursive implementation of the factorial function n!.

#!asm

;
; demo programm for CYY assembler cyysam
; calculate 5! = 5*4*3*2*1 = 120
;

;   -------------------------------------------------------------------
;
;   declare initialized data and constants
;
;   -------------------------------------------------------------------
section .data

start.value 5u64
null.value 0idx
one.value 1u64

;   -------------------------------------------------------------------
;
;   declare global variables
;
;   -------------------------------------------------------------------
section .bss

;
;
;
tmp 1u64

;   -------------------------------------------------------------------
;
;   keep the code here
;
;   -------------------------------------------------------------------
section .text

;   program start
MAIN:

;
;       set debug mode ON
;
dbgon

;   push start value on the stack
    pdata   start.value

;   call calculation
    call    FACTORIAL

;
;   dump result
;
    pbss tmp
    dump
    pop

;   exit
    ja      STOP


;
;   function: FACTORIAL()
;
FACTORIAL:

;   set up base register
    esba

;   push variable on the stack
;   this is the position relativ to base pointer that address the start value (a local variable)
    pdata   null.value
    pr

;   push 1
;   this is the termination condition (if local value equals 1 then start calculation and return)
    pdata   one.value

;   compare values and set jump register
    cmp 
    pop
;   local variable equals 1
;   start calculation and return
    je CALCULATE

;   push 1
    pdata   one.value

;   load local variable (again)
    pdata   null.value
    pr

;   sub (local value - 1)
    sub

;   recursion   
    call    FACTORIAL

;
;   return from recursion
;
    pop

CALCULATE:

;   load variable "tmp" and local value on the stack,
;   multiply and store value back
;   PSH &tmp
    pbss tmp

;   load local value
    pdata   null.value
    pr

    mul

;   pop
;   STVA &tmp
    store tmp

; prepare to return 
    reba
    ret

;
;   program stop
STOP:
;
;       set debug mode ON
;
;   dbgoff
    halt

Example to run this program on a linux system:

#!shell

build/cyysam --verbose -r tools/asmblr/examples/factorial.cysam

Wiki

cyy / CYYSAM

Assembler for the CYY VM

.DATA

.BSS

.TEXT

Example