New member here

[SteveMacD]

Hello everyone,

I have just joined up and am pretty much at the beginning of my Asm learning curve so I hope you will all forgive any silly questions. I've been playing around with PowerBasic at a hobby level for a little while and there seems to be a lot of PB'ers who slip Asm into their code. As someone who grew up in the days of the Vic20 and C64, when Asm was essential to get decent game performance, I've always been intrigued by this mysterious black art! Now I hope to find out more.

Look forward to chatting with you all.

Peace, Steven

[KeepingRealBusy]

Steve,

Welcome to the forum. enjoy! :icon14:

Dave.

[dedndave]

welcome to the forum Steve   :t

the admin guy, here, is Hutch - i am sure you have seen him in the PB forum

don't know how many more Steve's we can have, though - lol

[Vortex]

Hi Steve,

Welcome to the forum.

[hutch--]

Hi Steve,

Welcome on board. With the current versions of PB you can write very close to MASM style code once you are familiar with it. Here is a sample doing both simple PB function form and the lower level FASTPROC form which is near identical to MASM code..


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FUNCTION szCopy2(ByVal psrc as DWORD,ByVal pdst as DWORD) as DWORD

    #REGISTER NONE

    ! mov esi, psrc                     ; load source address
    ! mov edi, pdst                     ; load destination address
    ! xor ecx, ecx                      ; zero index
    ! jmp lbl0

  #align 16
  lbl0:
    ! movzx eax, BYTE PTR [esi+ecx]     ; read byte
    ! mov [edi+ecx], al                 ; write byte
    ! test eax, eax                     ; test for terminator
    ! jz lbl1                           ; exit loop on zero

    ! movzx eax, BYTE PTR [esi+ecx+1]   ; read byte
    ! mov [edi+ecx+1], al               ; write byte
    ! test eax, eax                     ; test for terminator
    ! jz lbl1                           ; exit loop on zero

    ! movzx eax, BYTE PTR [esi+ecx+2]   ; read byte
    ! mov [edi+ecx+2], al               ; write byte
    ! test eax, eax                     ; test for terminator
    ! jz lbl1                           ; exit loop on zero

    ! movzx eax, BYTE PTR [esi+ecx+3]   ; read byte
    ! mov [edi+ecx+3], al               ; write byte
    ! add ecx, 4

    ! test eax, eax                     ; test for terminator
    ! jnz lbl0                          ; loop back if not zero

  lbl1:
    ! mov FUNCTION, ecx                 ; return value is the copied length

End FUNCTION

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FASTPROC copybytes2

  ' ------------------------------------------
  ' arguments are, 1. [esp+4] source address
  '                2. [esp+8] destination address
  ' ------------------------------------------

    PREFIX "!"

    push esi                            ; preserve ESI, adds 4 to stack

    mov esi, [esp+4][4]                 ; load source address
    mov edx, [esp+8][4]                 ; load destination address
    xor ecx, ecx                        ; zero index
    jmp lbl0

  align 16
  lbl0:
    movzx eax, BYTE PTR [esi+ecx]       ; read byte
    mov [edx+ecx], al                   ; write byte
    test eax, eax                       ; test for terminator
    jz lbl1                             ; exit loop on zero

    movzx eax, BYTE PTR [esi+ecx+1]     ; read byte
    mov [edx+ecx+1], al                 ; write byte
    test eax, eax                       ; test for terminator
    jz lbl1                             ; exit loop on zero

    movzx eax, BYTE PTR [esi+ecx+2]     ; read byte
    mov [edx+ecx+2], al                 ; write byte
    test eax, eax                       ; test for terminator
    jz lbl1                             ; exit loop on zero

    movzx eax, BYTE PTR [esi+ecx+3]     ; read byte
    mov [edx+ecx+3], al                 ; write byte
    add ecx, 4

    test eax, eax                       ; test for terminator
    jnz lbl0                            ; loop back if not zero

  lbl1:
    pop esi                             ; restores ESI, subs 4 from stack
    ret 8                               ; balance stack on exit

    END PREFIX

END FASTPROC

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[Gunther]

Hi Steven,

welcome to the forum.

Gunther

[SteveMacD]

Thanks for all the welcomes guys!

Hutch: Thanks for going to the trouble of posting that code. It's a little bit beyond me right now, but I'm keen to get up to speed so I'm going to have a play around with it.