Which Assembly Language is descended from 6502?

[SIO99]

I've been studying a bit of 6502 Assembly Language recently, but so far I can't get the type in ALPA Assembler to Assemble anything! I plan to somehow learn 6502 soon. I hope this will enable me to move on and apply this knowledge on some more advanced computer system, using a more advanced CPU.

 

The question is, which Assembly Language(s) is or are similar to or descended from 6502? Can someone point out the similarities? I've read that there were 16 bit versions of the 6502 produced, but these are no longer made. I've studied some Z80 and 68000 in the past, but forgotten most of it.

[Bryan]

The 65816 is the 16-bit version of the 6502 and it is still made:

http://www.westerndesigncenter.com/wdc/w65c816s-chip.cfm

[candle]

first ARM cpu had similiar syntax, plus more registers to operate on

but i guess you can say that about just any assembler and processor

 

; hello world!
; a cool demo by eKid

;------------------------------------------
; vectors
;------------------------------------------

; um, reset vectors?

   section "VECTOR00",HOME[$00]
RST_00:
   jp    $100    ; $100 is program start in cartridge header.

   section    "VECTOR08",HOME[$08]
RST_08:
   jp    $100

   section    "VECTOR10",HOME[$10]
RST_10:
   jp    $100

   section    "VECTOR18",HOME[$18]
RST_18:
   jp    $100

   section    "VECTOR20",HOME[$20]
RST_20:
   jp    $100

   section    "VECTOR28",HOME[$28]
RST_28:
   jp    $100

   section    "VECTOR30",HOME[$30]
RST_30:
   jp    $100

   section    "VECTOR38",HOME[$38]
RST_38:
   jp    $100

; irq vectors
   
   section "VBLANK_VECTOR",HOME[$40]
VBL_VECT:
   reti    ; do nothing

   section "LCD_VECTOR",HOME[$48]
LCD_VECT:
   reti    ; do nothing

   section "TIMER_VECTOR",HOME[$50]
TIMER_VECT:
   reti    ; do nothing

   section "SERIAL_VECTOR",HOME[$58]
SERIAL_VECT:
   reti    ; do nothing

   section "JOYPAD_VECTOR",HOME[$60]
JOYPAD_VECT:
   reti    ; do nothing!

;---------------------------------------------------------
; cartridge header
;---------------------------------------------------------

   section "CHEADER",HOME[$100]
CARTRIDGE_HEADER:
   
   ; 0100-0103 Program Entry point
   jp    START
   nop
   
   ; 0104-0133 Nintendo logo, must be exact or gb will refuse to run program
   db    $CE,$ED,$66,$66,$CC,$0D,$00,$0B,$03,$73,$00,$83,$00,$0C,$00,$0D
   db    $00,$08,$11,$1F,$88,$89,$00,$0E,$DC,$CC,$6E,$E6,$DD,$DD,$D9,$99
   db    $BB,$BB,$67,$63,$6E,$0E,$EC,$CC,$DD,$DC,$99,$9F,$BB,$B9,$33,$3E
   
   ; 0134-013E Game title 11 chars
   db    "HELLO WORLD"
   
   ; 013f-0142 Manufacturer code
   db    "    "
   
   ; 0143 CGB flag
   db    $C0    ; cgb only
   
   ; 0144-0145 License code
   db    $00, $00
   
   ; 0146 SGB flag
   db    $00
   
   ; 0147 Cartridge Type
   db    $19
   
   ; 0148 ROM size
   db    $00    ; 32kb ROM
   
   ; 0149 RAM size
   db    $00    ; no cartridge ram
   
   ; 014A destination code
   db    $01    ; non-japan
   
   ; 014B old licensee code
   db    $33    ; $33 fixed, required
   
   ; 014C mask ROM version - handled by RGBFIX
   db    $00
   
   ; 014d header checksum - handled by RGBFIX
   db    $00    ; required!
   
   ; 014e-014f global checksum - handled by RGBFIX
   dw    $0000    ; not required

;------------------------------------------
; graphics
;------------------------------------------

   section "GRAPHICS",DATA

scribbles:
   include "scribbles.inc"

;------------------------------------------
; vram memory definition
;------------------------------------------

   section "VRAM_A",VRAM

; 4-bit font data
; 16 bytes per tile

vr_font:
   ds    27*16    ; reserve space

;------------------------------------------
; definitions
;------------------------------------------

DONUT_ISGOOD    EQU    $01

NR52        EQU    $FF26

LCDC        EQU    $FF40
STAT        EQU    $FF41
SCY        EQU    $FF42
SCX        EQU    $FF43
LY        EQU    $FF44
BCPS        EQU    $FF68
BCPD        EQU    $FF69
IE        EQU    $FFFF

;------------------------------------------
; program
;------------------------------------------

   section "HELLOWORLD",HOME[$150]
   
START::
   di    ; disable interrupts
   
   xor    a        ; disable sound (16% power saving)
   ld    [NR52], a
   
; wait for vblank

.dwait:
   ld    a, [LY]
   cp    a, 146        ; +2 
   jr    nz, .dwait

; disable LCD
   
   xor    a
   ld    [LCDC], a
   
; load scribble font 
   
   ld    bc, vr_font
   ld    hl, scribbles
   ld    de, 27*256 + 16
   
.copyfont:
   ld    a, [hl+]
   ld    [bc], a
   inc    bc
   dec    e
   jr    nz, .copyfont
   ld    e, 16
   dec    d
   jr    nz, .copyfont
   
   
; build a cool palette :]
   
   ld    a, $80        ; index 0, auto-inc
   ld    [bCPS], a
   
   ld    hl, BCPD
   ld    [hl], $ff    ; white
   ld    [hl], $7f
   ld    [hl], $1f    ; red
   ld    [hl], $00
   ld    [hl], $1f    ; red
   ld    [hl], $00
   ld    [hl], $1f    ; red
   ld    [hl], $00
   
; draw the text
; start by clearing the screen
   
   ld    hl, $9800
   xor    a
   ld    de, 1024

.clearscreen:
   ld    [hl], $00
   inc    hl
   dec    de
   jp    nz, .clearscreen
   
; write text
   
   ld    hl, str_message
   ld    bc, $9800-1
   
.writetext:
   ld    a, [hl+]
   cp    0
   jr    z, .endtext
   inc    bc
   sub    64
   jr    c, .writetext
   ld    [bc], a
   jr    .writetext
.endtext:

; center image

   ld    a, -68
   ld    [sCY], a
   ld    a, -36
   ld    [sCX], a
   
   ld    a, $91        ; enable lcd
   ld    [LCDC], a
   
   halt            ; crash program (low power consumption)
   ; rgbasm adds a NOP

str_message:
db    "HELLO@WORLD",0 ; the @ is a space 

[Marius]

I do not understand the question completely. But I would say try the Mac/65 assembler or the Synassembler if you want to do it on real Atari.

 

[sack-c0s]

ARM was designed to be easily learned by 6502 coders so you could say it is descended from it.

[JamesD]

Of modern CPUs, the closest assembly to the 6502 would be ARM.

ARM has many similarities to the 6502 as far as mnemonics go, but there are also some very clear differences between the 6502 and ARM.

For example, if you take a look at the jump/branch instructions, the 6502 has mnemonics for each condition and ARM has a generic jump followed by the condition and address in the operand field.

ARM further simplifies mnemonics (opcodes) and moves differences to the operand field to reduce the number of instructions and simplify decoding.

 

FWIW, in spite of their similarities, I'm not sure you can truly attribute ARM assembly strictly to the 6502.

If you look at the PDP series of computers, I'm sure you'll find they heavily influenced most CPUs in those days.

[atari8warez]

I do not understand the question completely. But I would say try the Mac/65 assembler or the Synassembler if you want to do it on real Atari.

 

He wanted to know which CPU(s) is more advanced, but syntacticaly similar to 6502 so that he can learn to program them easily knowing how to program a 6502.

[atari8warez]

ARM was designed to be easily learned by 6502 coders so you could say it is descended from it.

 

ARM takes some design queues from 6502 (like memory access architecture and lack of microcode) and have familiar looking opcodes but it's an advanced RISC processor and uses load/store architecture vs. the register-memory architecture of 6502. So it's not really a descendent of 6502 and the programmer would still need to learn a lot of new concepts, opcodes and ways of doing things...

[russg]

I've been studying a bit of 6502 Assembly Language recently, but so far I can't get the type in ALPA Assembler to Assemble anything! I plan to somehow learn 6502 soon. I hope this will enable me to move on and apply this knowledge on some more advanced computer system, using a more advanced CPU.

 

The question is, which Assembly Language(s) is or are similar to or descended from 6502? Can someone point out the similarities? I've read that there were 16 bit versions of the 6502 produced, but these are no longer made. I've studied some Z80 and 68000 in the past, but forgotten most of it.

 

Atari BASIC you can learn programming. The assembler for Atari does some things that aren't available in BASIC, except by USR calls. If you want to code for a modern machine, meaning a Windows PC, you can get Microsoft

Visual BASIC 2010 and Visual Studio for free. Visual BASIC is hard to get all the thousands of 'reserved words'. If you want to do something, say input a variable from the screen, in Atari BASIC it is 'INPUT #1,A$"

and DIM A$(10) or for a real number INPUT X, don't have to dimension the X. Atari BASIC only has real numbers, numbers up to billions +/- 9.9999999 E +97 to nine significant digits (actually only up to 1 billion).

 

To input a real number called 'cfreq' in VB 2010:

 

Dim cfreq as double

 

Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

Try

If Len(TextBox1.Text) > 0 Then

cfreq = Double.Parse(TextBox1.Text)

Label7.Text = cfreq

End If

Catch ex As Exception

MsgBox("non-number error")

TextBox1.Clear()

End Try

End Sub

 

Textbox1 and label7 you created when you created your 'form'. VB starts with a form, a windows box you add textbox and label to, then set parameters for them.

Then enter the code that happens when something changes in your form box.

 

The VB 2010 Express coding environment does most of the hard stuff automatically, the 'Private sub Textbox1....' and the end try end sub. Only the middle part with the

'cfreq = Double.Parse(TextBox1.Text)' do you enter. And that is also mostly prompted with many, many options. You just enter 'cfreq= ' then VB prompts you for the rest.

 

What I'm saying is you learn basic programming with Atari BASIC, init variables, loops, if then, gosub, but VB 2010 you Google what you want to do, eg.

enter variable in Visual BASIC and get a youtube video on how to do it. There's not so much of the tough parts you have to code, VB prompts you

for what you're trying to do. OH, the best part. VB 2010 Express is free, at least for 60 days or something. I developed my two VB 'apps' and haven't

seen the end of trial period yet. Youtube has tutorials on graphics too.

 

Here's a link to my VB programs.

http://www.russgilb.net

 

 

I'd say real Windows programmers use C#. Theres a C for Visual Studio 2012. I don't even know an assembler for 64 bit PC. I think 32 bit PC there was Eric Isaacsons A86 assembler. I did

some X86 coding many years ago.

Edited August 12, 2012 by russg

[JamesD]

I'd say real Windows programmers use C#. Theres a C for Visual Studio 2012. I don't even know an assembler for 64 bit PC. I think 32 bit PC there was Eric Isaacsons A86 assembler. I did

some X86 coding many years ago.

So what your saying is, you use C#?

[ZylonBane]

I think he has no comprehension what this thread is about, so he decided to pretend it was about BASIC.

[DamageX]

Freescale (formerly Motorola) 68HC08 microcontrollers are still around and they are as similar to 6502 as anything.

I don't even know an assembler for 64 bit PC.

NASM supports AMD64 instruction set.

[russg]

I'd say real Windows programmers use C#. Theres a C for Visual Studio 2012. I don't even know an assembler for 64 bit PC. I think 32 bit PC there was Eric Isaacsons A86 assembler. I did

some X86 coding many years ago.

So what your saying is, you use C#?

No, I'm not a real programmer, I'm a duffer. I think the OP wanted to know what a real programmer for PC uses, especially an assembler, which I don't know, but as usual, I have something to say,

even if it doesn't make a whole lot of sense. )

 

(Hey! I made an emoticon.)

Edited August 13, 2012 by russg

[russg]

I think he has no comprehension what this thread is about, so he decided to pretend it was about BASIC.

Let us know your answer.

[russg]

I'd say real Windows programmers use C#. Theres a C for Visual Studio 2012. I don't even know an assembler for 64 bit PC. I think 32 bit PC there was Eric Isaacsons A86 assembler. I did

some X86 coding many years ago.

So what your saying is, you use C#?

Real programmers do use MS Visual Studio. Visual C++ and Visual C# and even Visual BASIC. C#, C++ you can embed inline machine code, probably from assembled code.

 

Here's a pretty complete list of assemblers.

 

http://en.wikipedia.org/wiki/List_of_assemblers#ARM_assemblers

Edited August 13, 2012 by russg

[Roydea6]

That is a nice list,,,, should satisfy the OP.

[Gury]

And many real programmers also use Delphi and Lazarus.

[wesmond]

To OP - you said you want to learn 6502 "somehow" - the book you've mentioned elsewhere (130xe assembly language) is a pretty good reference - although I've not typed in ALPA. I learned the simple basics with Atari's Assembler Editor, but it was hard work and as a kid I didn't get that far. I've got into it more recently, and with much more success, with this combination:- 1. Eclipse (you'll need Java), 2. MADS assembler/compiler, 3. Altirra to run/debug/disassemble/step through... I'm sure there are alternatives to all three, but having an Eclipse/Java background I found that combination worked really well. Google or search these pages for all three.

 

To write something nice, you'll also need open in a webpage, if not on paper, Mapping the Atari, or De Re Atari probably, to tell you what memory addresses are for which bit of Atari's hardware - that's when the fun starts, as 6502 assembler on its own is really not that much - just reads/writes with memory, a bit of maths and logic, comparisons and branches... not much more.

 

Good luck...

[russg]

I'd say real Windows programmers use C#. Theres a C for Visual Studio 2012. I don't even know an assembler for 64 bit PC. I think 32 bit PC there was Eric Isaacsons A86 assembler. I did

some X86 coding many years ago.

So what your saying is, you use C#?

Real programmers do use MS Visual Studio. Visual C++ and Visual C# and even Visual BASIC. C#, C++ you can embed inline machine code, probably from assembled code.

 

Here's a pretty complete list of assemblers.

 

http://en.wikipedia....#ARM_assemblers

 

There's also John Harris (a REAL programmer) MAE, another macro 6502 assembler for A8.

Then there's a 'cross assembler' I think it is called, do 6502 assembly coding on a PC, called cc65.

Edited August 14, 2012 by russg

[flashjazzcat]

There's also John Harris MAE, another macro 6502 assembler.

Then there's a 'cross assembler' I think it is called, do 6502 assembly coding on a PC, called cc65.

 

MAE looks excellent. CC65 is a C compiler, but it has an assembler which can be used as a stand-alone tool, called CA65.