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ASZ80 Assembler

.z80 DIRECTIVE 

Format:  

        .z80 

The  .z80  directive enables processing of only the z80 specific
mnemonics.  HD64180/Z180 mnemonics encountered without the .hd64
directive will be flagged with an 'o' error.  

     The  .z80  directive  also  selects the Z80 specific cycles
count output when the -c command line option is specified.  


.hd64 DIRECTIVE 

Format:  

        .hd64 

The  .hd64  directive  enables  processing  of  the HD64180/Z180
specific mnemonics not included  in  the  Z80  instruction  set.
HD64180/Z180  mnemonics  encountered without the .hd64 directive
will be flagged with an 'o' error.  A synonym of .hd64 is .z180. 

     The  .hd64 directive also selects the HD64180/Z180 specific
cycles count output when the -c command line  option  is  speci-
fied.  



THE .__.CPU.  VARIABLE 


     The  value of the pre-defined symbol '.__.CPU.' corresponds
to the selected processor type.  The default value  is  0  which
corresponds  to the default processor type.  The following table
lists the processor types and associated values  for  the  ASZ80
assembler:  

        Processor Type            .__.CPU. Value
        --------------            --------------
            .z80                         0
        .hd64 / .z180                    1


     The  variable '.__.CPU.' is by default defined as local and
will not be output to the created .rel file.  The assembler com-
mand line options -g or -a will not cause the local symbol to be
output to the created .rel file.  

     The  assembler  .globl  directive may be used to change the
variable  type to  global  causing  its definition to be  output
to  the .rel file.  The inclusion of the definition of the vari-
able '.__.CPU.' might be  a  useful  means  of  validating  that
seperately  assembled files have been compiled for the same pro-
cessor type.  The linker will report an error for variables with
multiple non equal definitions.  


Z80 REGISTER SET AND CONDITIONS 


   The following is a complete list of register designations and
condition mnemonics:  

        byte registers  -       a,b,c,d,e,h,l,i,r
        register pairs  -       af,af',bc,de,hl
        word registers  -       pc,sp,ix,iy

        C -     carry bit set
        M -     sign bit set
        NC -    carry bit clear
        NZ -    zero bit clear
        P -     sign bit clear
        PE -    parity even
        PO -    parity odd
        Z -     zero bit set



Z80 INSTRUCTION SET 


  The following list specifies the format for each addressing
mode supported by ASZ80:  

        #data           immediate data
                        byte or word data

        n               byte value

        rg              a byte register
                        a,b,c,d,e,h,l

        rp              a register pair
                        bc,de,hl

        (hl)            implied addressing or
                        register indirect addressing

        (label)         direct addressing

        offset(ix)      indexed addressing with
                        an offset

        label           call/jmp/jr label

The  terms  data,  dir,  offset, and ext may all be expressions.
The terms dir and offset are not allowed to be  external  refer-
ences.  

   Note  that  not all addressing modes are valid with every in-
struction,  refer  to the Z80/HD64180/Z180  technical  data  for
valid modes.  

   The  following  tables  list  all  Z80/HD64180/Z180 mnemonics
recognized by the ASZ80 assembler.  The designation [] refers to
a required addressing mode argument.  

Inherent Instructions 

        ccf             cpd
        cpdr            cpi
        cpir            cpl
        daa             di
        ei              exx
        halt            neg
        nop             reti
        retn            rla
        rlca            rld
        rra             rrca
        rrd             scf


Implicit Operand Instructions 

        adc     a,[]            adc     []
        add     a,[]            add     []
        and     a,[]            and     []
        cp      a,[]            cp      []
        dec     a,[]            dec     []
        inc     a,[]            inc     []
        or      a,[]            or      []
        rl      a,[]            rl      []
        rlc     a,[]            rlc     []
        rr      a,[]            rr      []
        rrc     a,[]            rrc     []
        sbc     a,[]            sbc     []
        sla     a,[]            sla     []
        sra     a,[]            sra     []
        srl     a,[]            srl     []
        sub     a,[]            sub     []
        xor     a,[]            xor     []


Load Instruction 

        ld      rg,[]           ld      [],rg
        ld      (bc),a          ld      a,(bc)
        ld      (de),a          ld      a,(de)
        ld      (label),a       ld      a,(label)
        ld      (label),rp      ld      rp,(label)
        ld      i,a             ld      r,a
        ld      a,i             ld      a,r
        ld      sp,hl           ld      sp,ix
        ld      sp,iy           ld      rp,#data

        ldd                     lddr
        ldi                     ldir


Call/Return Instructions 

        call    C,label         ret     C
        call    M,label         ret     M
        call    NC,label        ret     NC
        call    NZ,label        ret     NZ
        call    P,label         ret     P
        call    PE,label        ret     PE
        call    PO,label        ret     PO
        call    Z,label         ret     Z
        call    label           ret


Jump and Jump to Subroutine Instructions 

        jp      C,label         jp      M,label
        jp      NC,label        jp      NZ,label
        jp      P,label         jp      PE,label
        jp      PO,label        jp      Z,label

        jp      (hl)            jp      (ix)
        jp      (iy)            jp      label

        djnz    label

        jr      C,label         jr      NC,label
        jr      NZ,label        jr      Z,label
        jr      label


Bit Manipulation Instructions 

        bit     n,[]
        res     n,[]
        set     n,[]


Interrupt Mode and Reset Instructions 

        im      n
        im      n
        im      n
        rst     n


Input and Output Instructions 

        in      a,(n)           in      rg,(c)
        ind                     indr
        ini                     inir

        out     (n),a           out     (c),rg
        outd                    otdr
        outi                    otir


Register Pair Instructions 

        add     hl,rp           add     ix,rp
        add     iy,rp

        adc     hl,rp           sbc     hl,rp

        ex      (sp),hl         ex      (sp),ix
        ex      (sp),iy
        ex      de,hl
        ex      af,af'

        push    rp              pop     rp


HD64180/Z180 Specific Instructions 

        in0     rg,(n)
        out0    (n),rg

        otdm                    otdmr
        otim                    otimr

        mlt     bc              mlt     de
        mlt     hl              mlt     sp

        slp

        tst     a
        tstio   #data

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Last Updated: April 2009