## ASRAB Assembler

####

    ACKNOWLEDGMENT

       Thanks to Ulrich Raich and Razaq Ijoduola for their contribution
    of the ASRAB cross assembler.

       Ulrich Raich and Razaq Ijoduola
       PS Division
       CERN
       CH-1211 Geneva-23

       Ulrich dot Raich at cern dot ch

####

    PROCESSOR SPECIFIC DIRECTIVES

       The  ASRAB  assembler is a port of the ASZ80 assembler.  This
    assembler can process Rabbit 2000/3000 (default), HD64180 (Z180),
    and  Z80  code.   The  following  processor  specific  assembler
    directives specify which processor to target when processing the
    input assembler files.

    Format:

            .r2k

    The  .r2k  directive  enables processing of the Rabbit 2000/3000
    specific mnemonics.  Mnemonics not associated  with  the  Rabbit
    2000/3000 processor will be flagged with an <o> error.  Address-
    ing modes not supported by the Rabbit 2000/3000 will be  flagged
    with  an <a> error.  A synonym of .r2k is .r3k.  The default as-
    sembler mode is .r2k.

         The  .r2k  directive  also  selects  the  Rabbit  2000/3000
    specific cycles count output when the -c command line option  is
    specified.

    Format:

            .hd64

    The  .hd64  directive  enables  processing of the HD64180 (Z180)
    specific mnemonics not included  in  the  Z80  instruction  set.
    Rabbit  2000/3000  mnemonics encountered will be flagged with an
    <o> error.  Addressing modes not supported by the HD64180 (Z180)
    will be flagged with an <a> 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.

    Format:

            .z80

    The  .z80  directive  enables  processing  of  the  Z80 specific
    mnemonics.  HD64180 and Rabbit 2000/3000 specific mnemonics will
    be flagged with an <o> error.  Addressing modes not supported by
    the z80 will be flagged with an <a> error.

         The  .z80  directive  also  selects the Z80 specific cycles
    count to be output when.

    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  ASRAB
    assembler:

            Processor Type            .__.CPU. Value
            --------------            --------------
             .r2k / .r3k                     0
            .hd64 / .z180                    1
                .z80                         2

         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.

####

    RABBIT INSTRUCTION SYMBOLS

            b       Bit select
                            (000 = bit 0, 001 = bit 1,
                             010 = bit 2, 011 = bit 3,
                             100 = bit 4, 101 = bit 5,
                             110 = bit 6, 111 = bit 7)
            cc      Condition code select
                            (00 = NZ, 01 = Z, 10 = NC, 11 = C)
            d       8-bit (signed) displacement.
                    Expressed in two\'s complement.
            dd      word register select-destination
                            (00 = BC, 01 = DE, 10 = HL, 11 = SP)
            dd'     word register select-alternate
                            (00 = BC', 01 = DE', 10 = HL')
            e       8-bit (signed) displacement added to PC.
            f       condition code select
                            (000 = NZ, 001 = Z, 010 = NC, 011 = C,
                             100 = LZ/NV, 101 = LO/V, 110 = P, 111 = M)
            m       the most significant bits(MSB) of a 16-bit constant
            mn      16-bit constant
            n       8-bit constant or the least significant bits(LSB)
                    of a 16-bit constant
            r, g    byte register select
                            (000 = B, 001 = C, 010 = D, 011 = E,
                             100 = H, 101 = L, 111 = A)
            ss      word register select-source
                            (00 = BC, 01 = DE, 10 = HL, 11 = SP)
            v       Restart address select
                            (010 = 0020h, 011 = 0030h, 100 = 0040h,
                             101 = 0050h, 111 = 0070h)
            x       an 8-bit constant to load into the XPC
            xx      word register select
                            (00 = BC, 01 = DE, 10 = IX, 11 = SP)
            yy      word register select
                            (00 = BC, 01 = DE, 10 = IY, 11 = SP)
            zz      word register select
                            (00 = BC, 01 = DE, 10 = HL, 11 = AF)

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

    The  terms  m, mn, n, and x may all be expressions.  The terms b
    and v are not allowed to be external references.

####

    RABBIT INSTRUCTION SET

       The  following list of instructions (with explicit addressing
    modes) are available in the  Rabbit  2000/3000  assembler  mode.
    Those instructions denoted by an asterisk (*) are additional in-
    structions not available in the HD64180 or Z80 assembler mode.

             ADC A,n                 DEC IX                  LD A,EIR
             ADC A,r                 DEC IY                  LD A,IIR
             ADC A,(HL)              DEC r                  *LD A,XPC
             ADC A,(IX+d)            DEC ss                  LD A,(BC)
             ADC A,(IY+d)            DEC (HL)                LD A,(DE)
             ADC HL,ss               DEC (IX+d)              LD A,(mn)
             ADD A,n                 DEC (IY+d)             *LD dd,BC
             ADD A,r                 DJNZ e                 *LD dd,DE
             ADD A,(HL)                                      LD dd,mn
             ADD A,(IX+d)            EX AF,AF                LD dd,(mn)
             ADD A,(IY+d)            EX DE,HL                LD EIR,A
             ADD HL,ss               EX DE,HL               *LD HL,IX
             ADD IX,xx               EX (SP),HL             *LD HL,IY
             ADD IY,yy               EX (SP),IX             *LD HL,(HL+d)
            *ADD SP,d                EX (SP),IY             *LD HL,(IX+d)
            *ALTD                    EXX                    *LD HL,(IY+d)
            *AND HL,DE                                       LD HL,(mn)
            *AND IX,DE               INC IX                 *LD HL,(SP+n)
            *AND IY,DE               INC IY                  LD IIR,A
             AND n                   INC r                  *LD IX,HL
             AND r                   INC ss                  LD IX,mn
             AND (HL)                INC (HL)                LD IX,(mn)
             AND (IX+d)              INC (IX+d)             *LD IX,(SP+n)
             AND (IY+d)              INC (IY+d)             *LD IY,HL
                                    *IOE                     LD IY,mn
             BIT b,r                *IOI                     LD IY,(mn)
             BIT b,(HL)             *IPRES                  *LD IY,(SP+n)
             BIT b,(IX+d)           *IPSET 0                 LD r,g
             BIT b,(IY+d)           *IPSET 1                 LD r,n
            *BOOL HL                *IPSET 2                 LD r,(HL)
            *BOOL IX                *IPSET 3                 LD r,(IX+d)
            *BOOL IY                                         LD r,(IY+d)
                                     JP f,mn                 LD SP,HL
             CALL mn                 JP mn                   LD SP,IX
             CCF                     JP (HL)                 LD SP,IY
             CP n                    JP (IX)                *LD XPC,A
             CP r                    JP (IY)                 LD (BC),A
             CP (HL)                 JR cc,e                 LD (DE),A
             CP (IX+d)               JR e                    LD (HL),n
             CP (IY+d)                                       LD (HL),r
             CPL                    *LCALL x,mn

            *LD (HL+d),HL           *POP IP                  SBC A,n
            *LD (IX+d),HL            POP IX                  SBC A,r
             LD (IX+d),n             POP IY                  SBC A,(HL)
             LD (IX+d),r             POP zz                  SBC HL,ss
            *LD (IY+d),HL           *PUSH IP                 SBC (IX+d)
             LD (IY+d),n             PUSH IX                 SBC (IY+d)
             LD (IY+d),r             PUSH IY                 SCF
             LD (mn),A               PUSH zz                 SET b,r
             LD (mn),HL                                      SET b,(HL)
             LD (mn),IX              RA                      SET b,(IX+d)
             LD (mn),IY              RES b,r                 SET b,(IY+d)
             LD (mn),ss              RES b,(HL)              SLA r
            *LD (SP+n),HL            RES b,(IX+d)            SLA (HL)
            *LD (SP+n),IX            RES b,(IY+d)            SLA (IX+d)
            *LD (SP+n),IY            RET                     SLA (IY+d)
             LDD                     RET f                   SRA r
             LDDR                   *RETI                    SRA (HL)
             LDI                    *RL DE                   SRA (IX+d)
             LDIR                    RL r                    SRA (IY+d)
            *LDP HL,(HL)             RL (HL)                 SRL r
            *LDP HL,(IX)             RL (IX+d)               SRL (HL)
            *LDP HL,(IY)             RL (IY+d)               SRL (IX+d)
            *LDP HL,(mn)             RLA                     SRL (IY+d)
            *LDP IX,(mn)             RLC r                   SUB n
            *LDP IY,(mn)             RLC (HL)                SUB r
            *LDP (HL),HL             RLC (IX+d)              SUB (HL)
            *LDP (IX),HL             RLC (IY+d)              SUB (IX+d)
            *LDP (IY),HL             RLCA                    SUB (IY+d)
            *LDP (mn),HL            *RR DE
            *LDP (mn),IX            *RR HL                   XOR n
            *LDP (mn),IY            *RR IX                   XOR r
             LJP x,mn               *RR IY                   XOR (HL)
             LRET                    RR r                    XOR (IX+d)
                                     RR (HL)                 XOR (IY+d)
            *MUL                     RR (IX+d)
                                     RR (IY+d)
             NEG                     RRC r
             NOP                     RRC (HL)
                                     RRC (IX+d)
            *OR HL,DE                RRC (IY+d)
            *OR IX,DE                RRCA
            *OR IY,DE                RST v
             OR n
             OR r
             OR (HL)
             OR (IX+d)
             OR (IY+d)

####

    Z80/HD64180 INSTRUCTION SYMBOLS

      The following list specifies the format for each Z80/HD64180
    addressing mode supported by ASRAB:

            #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

            (ix+offset)     indexed addressing with
             offset(ix)     an offset

            label           call/jmp/jr label

    The  terms  data, n, label, and offset may all be expressions.

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

####

    Z80/HD64180 INSTRUCTIONS

       The  following  tables  list all Z80/HD64180 mnemonics recog-
    nized by the ASRAB 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 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: March 2025