## ASF8 Assembler

####

       The ASF8 assembler supports the F8 and 3870 processor cores.

    F8 REGISTERS

       The  following  is a list of register designations recognized
    by the ASF8 assembler:

            r0-r11  -       Registers

            j       -       Scratch Pad Register r9

            hu      -       MSB of register H the
                              Data Counter Buffer Register
                              Scratch Pad Register r10
            hl      -       LSB of register H the
                              Data Counter Buffer Register
                              Scratch Pad Register r11

            ku      -       MSB of register K the
                              Stack Buffer Register
            kl      -       LSB of register K the
                              Stack Buffer Register

            qu      -       MSB of register Q a
                              Buffer Register for the
                              Data Counter or Program Counter
            ql      -       LSB of register Q a
                              Buffer Register for the
                              Data Counter or Program Counter

            a       -       Accumulator

            is      -       Scratch Pad Address Register (ISAR)

            w       -       Status Register

            s       -       Register Addressed
                            by is (unchanged)

            i       -       Register Addressed
                            by is (incremented)

            d       -       Register Addressed
                            by is (decremented)

            pc0     -       Program Counter
            or p0, pc

            pc1     -       Program Counter Buffer or
            or p1, p        Stack Register

            dc0     -       Data Counter
            or d0, dc

    F8 INSTRUCTION SET

       The  following  list specifies the format for each addressing
    mode supported by ASF8:

            #nibble         immediate  4-Bit data
            #byte           immediate  8-Bit data
            #word           immediate 16-Bit data

            #t3             3-Bit test condition
                            [Zero Carry Sign]

            #t4             4-Bit test condition
                            [Overflow Zero Carry Sign]

            r               register r0-r11 addressing and
                            indirect addressing s, i, and d
                            j is equivalent to r9
                            hu (MSB of h) is equivalent to r10
                            hl (LSB of h) is equivalent to r11

            ku and kl       MSB and LSB of k register

            qu and ql       MSB and LSB of q register

            h, k, or q      16-Bit registers
            p0, pc0, or pc
            p1 or p
            d0, dc0, or dc

            w               status register

            is              Indirect Scratchpad Address Register

            label           call/jmp/branch label

    The  terms  nibble, byte, word, t3, t4, and label may all be ex-
    pressions.

       The  following tables list all F8 mnemonics recognized by the
    ASF8 assembler.

    Accumulator Group Instructions

            lnk                     ai      #byte
            ni      #byte           clr
            ci      #byte           com
            xi      #byte           inc
            li      #byte           lis     #nibble
            oi      #byte           sl      1
            sl      4               sr      1
            sr      4

    ranch Instructions

            bc      label           bp      label
            bz      label           bt      #t3,label
            bm      label           bnc     label
            bno     label           bnz     label
            bf      #t4,label       br7     label
            br      label           jmp     label

    Memory Reference Instructions

            am                      amd
            nm                      cm
            xm                      lm
            om                      st

    Address Register Instructions

            adc                     pk
            pi      #word           xdc
            lr      dc,q            lr      dc,h
            dci     #word           lr      p0,q
            lr      p,k             pop
            lr      q,dc            lr      h,dc
            lr      k,p

    Scratchpad Register Instructions

            as      r               asd     r
            ds      r
            lr      a,r
            lr      a,ku            lr      a,kl
            lr      a,qu            lr      a,ql
            lr      r,a
            lr      ku,a            lr      kl,a
            lr      qu,a            lr      ql,a
            ns      r               xs      r

    Miscellaneous Instructions

            di                      ei
            in      #byte           ins     #nibble
            out     #byte           outs    #nibble
            lr      is,a            lr      a,is
            lr      w,j             lr      j,w
            lisl    #0-#7           lisu    #0-#7
            nop

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###### Last Updated: March 2025