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AS68k Assembler

   The assembler supports the full instruction set of the 68000,
68008, 68010 and 68020 processors.  

   The assembler options to select the desired processor are:  

    .68000 - 68000 16/24-bit data/address
    .68008 - 68008  8/22-bit data/address
    .68010 - 68010 16/24-bit data/address
    .68020 - 68020 32/32-bit data/address

   The  assembler  makes  no distinction concerning the data and
address bus widths of the underlying processor  type.   Instruc-
tions  not  supported  by  the  specific processor will report a
warning.  

   In  addition, the floating point instruction set of the 68881
and 68882 floating point coprocessors are supported:  

    .68881 - 68881 Floating Point Processor
    .68882 - 68882 Floating Point Processor

   The  cycle counts for each instruction is processor dependent
and is determined by the selected options.  Because  the  number
of instruction cycles for some instructions exceed the normal 99
cycle ASxxxx limit, the maximum has been increased  to  999  for
the  680xx  processors.   When  the floating point processor in-
structions are enabled the maximum is increased to 9999 as  some
of  the  packed  floating point instructions exceed 2000 cycles.
The cycle counts were extracted from the tables contained in the
book  "The  Motorola  MC68000  Microprocessor  Family:  Assembly
Language, Interface Design, and  System  Design"  by  Thomas  L.
Harmon  and  Barbara  Lawson (Prentice Hall, 1985), the "MC68020
32-Bit  Microprocessor  User's  Manual"  (Motorola  Inc.   1984,
1985),  and  the  "MC68881/MC68882  Floating  Point  Coprocessor
User's Manual" Second Edition, (Motorola Inc.  1989).  

AS68K ASSEMBLER SPECIFIC DIRECTIVES 

.setdp Directive 

Format:  

        .setdp [base [,area]] 

            The .setdp directive is used to inform the
            assembler of the current direct page region
            and the offset address within the selected
            area.  The normal invocation methods are:

                .area   DIRECT  (PAG)
                .setdp

                or

                .setdp  #,DIRECT


   AS68K  has  two  paging  regions, the first 32K bytes and the
last 32K bytes of the 32-bit addressing space.   The  paged  ad-
dressing      ranges      are      0x00000000-0x00007FFF     and
0xFFFF8000-0xFFFFFFFF.  Define a different area for each of  the
regions:  

        .area   LOPAGE  (PAG)
        .setdp  0x00000000,LOPAGE

        .area   HIPAGE  (PAG)
        .setdp  0xFFFF8000,HIPAGE


   These  two regions must both be linked with a base address of
0x00000000 to position them so that  instructions  can  use  the
16-bit  short  forms  to  access these regions.  Explicit direct
page addressing is invoked by using the '*' prefix to a label or
symbol.  Automatic direct page addressing can be invoked by ena-
bling the autodpcnst (Automatic Direct  Page  Constants)  and/or
the autodpsmbl (Automatic Direct Page Symbols) options.  

   The  assembler  verifies  that  any  local variable used in a
direct variable reference is located in this area.  Local  vari-
able  and  constant value direct access addresses are checked to
be within the paging address ranges.  The linker will check  all
external  direct page relocations to verify that they are within
the correct area.  

   External  global  references are normally specified using the
.globl directive.  However the two paging areas of AS68K require
additional  information  for  the  external references.  This is
done by the directives .lodpgbl and .hidpgbl.  


.lodpgbl Directive 


   Format:  

        .lodpgbl arg1, arg2, ...  

            Where the arguments are labels or
            symbols with values that are in the
            0x00000000-0x00007FFF direct page.
            If the low page area has not been
            specified then the arguments are
            defined as being in the current area.


.hidpgbl Directive 

Format:  

        .hidpgbl arg1, arg2, ...  

            Were the arguments are labels or
            symbols with values that are in the
            0xFFFF8000-0xFFFFFFFF direct page.
            If the high page area has not been
            specified then the arguments are
            defined as being in the current area.


.qword 

   Format:  

        .qword arg1, arg2, ...  

            .qword creates a 64-Bit integer which
            causes four words of storage to be
            generated for each argument.


.flt16, .flt32, .flt64, .flt96, and .fltpk 

   There  are five supported floating point formats available in
the AS68K assembler where arg1, arg2, ...  represent one or more
floating-point numbers.
  
Format:  

        .flt16 arg1, arg2, ...  

            .flt16 causes one word of storage
            to be generated for each argument.

        Word: 16-Bit Floating Point Format:

        15      14     7        6     0
         S      EEEEEEEE        MMMMMMM

                Mantissa  (7 bits)
                Exponent  (8 bits) Biased
                Sign      (1 bit)

Format:  

        .flt32 arg1, arg2, ...  

            .flt32 causes two words of storage
            to be generated for each argument.

        Single: 32-Bit Floating Point:

        31      30    23        22        0
         S      EEEEEEEE        MMM.....MMM

                Mantissa  (23 bits)
                Exponent  (8 bits) Biased
                Sign      (1 bit)

Format:  

        .flt64 arg1, arg2, ...  

            .flt64 generates 4 words of storage
            for each argument.

        Double: 64-Bit Floating Point

        63      62       52     51        0
         S      EEEEEEEEEEE     MMM.....MMM

                Mantissa  (52 bits)
                Exponent  (11 bits) Biased
                Sign      (1 bit)
Format:  

        .flt96 arg1, arg2, ...  

            .flt96 generates 6 words of storage
            for each argument.

        Extended: 64-Bit Floating

        95      94       80  79   64 63 62        0
         S      EEEEEEEEEEE  0000000  1 MMM.....MMM

                Sign      (1 bit)
                Exponent  (15 bits)  Biased
                Padding   (16 bits)  Always 0
                Integer   (1 bit)    Always 1
                Mantissa  (63 bits)

Format:  

        .fltpk arg1, arg2, ...  

            .fltpk generates 6 words of storage
            for each argument as packed BCD
            (binary coded decimal) with a 17-digit
            mantissa and a 3-digit exponent.

        Packed: 17-Digit BCD Packed

        95  94  93 92  91 80  79 68  67        0
        SM  SE  YYYYY  EEEEE  xxxxx  MMM.....MMM

                Sign Mantissa  (1 bit)
                Sign Exponent  (1 bit)
                Special Cases  (2 bits)
                Exponent       (3 digits)  000-999
                Don't Care     (12 bits)
                Mantissa       (17 digits)

   The arguments are evaluated and the results are stored in the
object module.  Unlike the .word directive only the sign  opera-
tors   (+)   and  (-)  may  be  used  in  the  evaluation  of  a
floating-point argument.  No arithmetic operations  are  allowed
in the floating-point argument.  

   A floating-point number is represented by a string of decimal
digits.  The string (which can be a single digit in length)  may
contain  an optional decimal point and may be followed by an op-
tional exponent indicator in the form of 'E' or 'e' followed  by
a  signed  decimal integer exponent.  The number may not contain
embedded blanks, tabs, or angle brackets and may not be  an  ex-
pression.  

   The  AS68K  assembler returns a value of the appropriate size
and precision via one of  the  floating-point  directives.   The
values  returned  may be truncated or rounded as selected by the
'.enabl (fpt)' or '.dsabl (fpt)' respectively.  

   Floating-point numbers are normally rounded.  That is, when a
floating-point number exceeds the limits of the field  in  which
it is to be stored, the high-order bit of the unretained portion
is added to the low-order bit of the retained portion.  


^F - The Temporary Floating-Point Operator 

   Format:  

        ^F 

   ^F  is  a unary operator for numeric control which allows you
to specify an  argument  that  is  either  a  1-word  or  2-word
floating-point number.  For example, the following statement:  

        A:      MOVE.W  #^F3.7,D0

creates an immediate 1-word floating-point number containing the
value 3.7 formatted as shown in the .flt16 description in a pre-
vious section.  

The following statement:  

        B:      MOVE.L  #^F3.7,D0

creates an immediate 2-word floating-point number containing the
value 3.7 formatted as shown in the .flt32 description in a pre-
vious section.  

   The ^F operator is only allowed in an instruction.  


.enabl and .dsabl 

   Format:  

        .enabl (arg1, arg2, ...) 
        .dsabl (arg1, arg2, ...) 

where:  arg1, arg2, ...    represent one or more
                           of the following options

        alt          Allow Alternate Instructions
        fpt          Floating-Point Truncation
        autodpcnst   Automatic Direct Paging For Constants
        autodpsmbl   Automatic Direct Paging For Symbols

alt:  controls whether the automatic translation of instructions
to alternate instruction  forms  is  enabled.   The  default  is
enabled.  The following translations may be performed:  

        MOVE [],An  ->  MOVEA [],An
        MOVE #,Dn   ->  MOVEQ #,Dn  (#: -128 to +127)

        ADD Dn,An   ->  ADDA Dn,An
        ADD #,Dn    ->  ADDI #,Dn
        ADD #,Dn    ->  ADDQ #,Dn   (#: 1 to 8)

        AND #,Dn    ->  ANDI #,Dn

        CMP [],An   ->  CMPA [],An
        CMP #,Dn    ->  CMPI #,Dn

        EOR #,[]    ->  EORI #,[]

        OR #,Dn     ->  ORI #,Dn

        SUB An,Dn   ->  SUBA An,Dn
        SUB #,Dn    ->  SUBI #,Dn
        SUB #,Dn    ->  SUBQ #,Dn   (#: 1 to 8)


   fpt:   controls  whether floating-point truncation is active.
Normal mode is fpt disabled and rounding is enabled.  

   autodpcnst:   controls  whether  instructions  without length
qualifies, .B, .W, .L, can automatically use  short  forms  when
the  constants  are  within  the ranges of 0x00000000-0x00007FFF
(low  paging  region)  or  0xFFFF8000-0xFFFFFFFF  (high   paging
region)  or  are external globals.  The paging regions must have
been specified for this option to take effect.  The  default  is
enabled.  

   autodpsmbl:   controls  whether  instructions  without length
qualifies, .B, .W, .L, can automatically use  short  forms  when
the  symbols are within the ranges of 0x00000000-0x00007FFF (low
paging region) or 0xFFFF8000-0xFFFFFFFF (high paging region)  or
are  external globals.  The paging regions must have been speci-
fied for this option to take effect.  The default is enabled.  

680XX REGISTER SET 


   The following is a list of the 680xx registers used by AS68K.
Eight 32-bit data registers provide data as  bytes,  words,  and
longs.   Eight  address  registers provide addresses as words or
longs.  Other registers include the 32-bit program  counter  and
the  8-bit  status  register.   The  control  registers  are not
described in this document.  

    Data Registers
        |- Long ---------------------------|
                         |- Word-----------|
                                  |- Byte -|
         31            16 15     8 7      0
        |----------------|--------|--------|
        |-               |        |       -| D0
        |----------------|--------|--------|
        |-               |        |       -| D1
        |----------------|--------|--------|
        |-               |        |       -| D2
        |----------------|--------|--------|
        |-               |        |       -| D3
        |----------------|--------|--------|
        |-               |        |       -| D4
        |----------------|--------|--------|
        |-               |        |       -| D5
        |----------------|--------|--------|
        |-               |        |       -| D6
        |----------------|--------|--------|
        |-               |        |       -| D7
        |----------------|--------|--------|


    Address Registers
        |- Long --------------------------|
                         |- Word----------|
         31            16 15             0
        |----------------|----------------|
        |-               |               -| A0
        |----------------|----------------|
        |-               |               -| A1
        |----------------|----------------|
        |-               |               -| A2
        |----------------|----------------|
        |-               |               -| A3
        |----------------|----------------|
        |-               |               -| A4
        |----------------|----------------|
        |-               |               -| A5
        |----------------|----------------|
        |-               |               -| A6
        |----------------|----------------|
        |-       User Stack Pointer      -|
        |----------------|----------------| A7 / SP
        |-    Supervisor Stack Pointer   -|
        |----------------|----------------|

         31                             0
        |--------------------------------|
        |-       Program Counter         |
        |--------------------------------|

                       |--------|--------|
        Status Register| System |  User  |
                       |--------|--------|

COMMON 680XX ADDRESSING MODES 

The addressing modes supported by all 680xx processors:

 Mode   Register   Syntax           Addressing Mode     
 -----  --------  --------    ----------------------------
  000    Reg #       Dn       Data Reg Dir
  001    Reg #       An       Addr Reg Dir
  010    Reg #      (An)      Addr Reg Ind
  011    Reg #      (An)+     Addr Reg Ind w/Postinc
  100    Reg #      -(An)     Addr Reg Ind w/Predec
  101    Reg #      d16(An)   Addr Reg Ind w/Disp
             or    (d16,An)
  110    Reg #    d8(An,Rn)   Addr Reg Ind w/Disp w/Index
             or  (d8,An,Rn)
  111     000        xxx      Absolute Short
             or     (xxx).W
  111     001       xxxxx     Absolute Long
             or    (xxxxx).L
  111     010       d16(PC)   Prog Ctr Ind w/Disp
             or    (d16,PC)
  111     011     d8(PC,Rn)   Prog Ctr Ind w/Disp w/Index
             or  (d8,PC,Rn)
  111     100       #xxx      Immediate
             or    #(xxx).W   Short Immediate
             or    #(xxx).L   Long Immediate

        Where Rn is An or Dn
        Note that Rn supports Rn.W and Rn.L forms.

        The following short forms are also supported:
                @An     <==>    (An)
                @An+    <==>    (An)+
               -@An     <==>   -(An)

ADDITIONAL 68020 ADDRESSING MODES 

These additional addressing modes are supported
only on the 68020 processor:

 Mode   Register   Syntax           Addressing Mode     
 -----  --------  --------    ----------------------------
  110    Reg #    d16(An,Rn)  Addr Reg Ind w/Disp w/Index
             or  (d16,An,Rn)
  110    Reg #    d32(An,Rn)  Addr Reg Ind w/Disp w/Index
             or  (d32,An,Rn)

  111     011     d16(PC,Rn)  Prog Ctr Ind w/Disp w/Index
             or  (d16,PC,Rn)
  111     011     d32(PC,Rn)  Prog Ctr Ind w/Disp w/Index
             or  (d32,PC,Rn)

  110    Reg #  ([bd,An,Xn],od)
  110    Reg #  ([bd,An],Xn,od)

  111     011   ([bd,PC,Xn],od)
  111     011   ([bd,PC],Xn,od)

  Where:  bd is an offset - optional: (bd).W or (bd).L
          An is an address register
          PC is the program counter
          Xn is An or Dn  - optional: An.W/An.L/Dn.W/Dn.L
              a scaling factor may be applied to Xn with
              an optional suffix of *1, *2, *4, or *8
          od is an offset - optional: (od).W or (od).L

          Rn is An or Dn
          Note that Rn supports Rn.W and Rn.L forms.

680XX INSTRUCTION SET 

   The  following  tables list all the instructions found in the
68000, 68008, 68010, and 68020 microprocessors.  The  (.B,.W,.L)
indicates  an  instruction  has byte, word, and long forms.  The
brackets '[]' indicate one of the  described  addressing  modes.
Note that most instructions do not support all addressing modes,
see the appropriate data sheets for allowed modes.  

   For  those  instructions having multiple forms and there is a
word form the assembler default is to use the word form.  

MOVE Instructions 

        MOVE (.B,.W,.L) [],[]   Source To Destination
      * MOVE (.W)       CCR,[]  From Condition Code Register
        MOVE (.W)       [],CCR  To Condition Code Register
      * MOVE (.W)       SR,[]   From Status Register
        MOVE (.W)       [],SR   To Status Register
        MOVE (.L)       USP,An  From User Stack Pointer
        MOVE (.L)       An,USP  To User Stack Pointer
        MOVEA (.W,.L)   [],An   To Address Register
      * MOVEC (.L)      Rc,Rn   From Control Register
      * MOVEC (.L)      Rn,Rc   To Control register
        MOVEM (.W,.L)   Rlist,[]  From Registers In List
        MOVEM (.W,.L)   [],Rlist  To Registers In List
        MOVEP (.W,.L)   Dn,d(An)  Data To Alternate Bytes
        MOVEP (.W,.L)   d(An),Dn  Data From Alternate Bytes
        MOVEQ (.L)       #,[]   Signed 8-Bit # To Destination
      * MOVES (.B,.W,.L) Rn,[]  To Address Space
      * MOVES (.B,.W,.L) [],Rn  From Address Space

   * -- 68010/68020 Instructions


Double Operand 

        ADD  (.B,.W,.L) [],[]   ADD Source To Destination
        ADDA (.W,.L)    [],An
        ADDX (.B,.W,.L) Dn,Dn or -(An),-(An)
        AND  (.B,.W,.L) [],[]   AND Source With Destination
        CMP  (.B,.W,.L) [],[]   Destination - Source, Set CCs
        CMPA (.W,.L)    [],An
        CMPM (.B,.W,.L) (An)+,(An)+
      # DIVS (.W)       [],Dn   Signed Destination/Source
      # DIVU (.W)       [],Dn   UnSigned Destination/Source
        EOR  (.B,.W,.L) Dn,[]   XOR Source With Destination
      # MULS (.W)       [],Dn   Signed Source*Destination
      # MULU (.W)       [],Dn   UnSigned Source*Destination
        OR   (.B,.W,.L) [],[]   Source ORed With Destination
        SUB  (.B,.W,.L) [],[]   Subtract Source From Destination
        SUBA (.W,.L)    [],An
        SUBX (.B,.W,.L) Dn,Dn or -(An),-(An)

   # -- 68020 Added .L Functionality


Decimal Instructions 

        ABCD (.B)       Dn,Dn   Add Decimal With X (Carry)
        ABCD (.B)       -(An),-(An)
        NBCD (.B)       []      Negate Decimal With X (Carry)
        SBCD (.B)       Dn,Dn   Subtract Decimal With X (Carry)
        SBCD (.B)       -(An),-(An)


Immediate Instructions 

        ADDI (.B,.W,.L)  #,[]   ADD Immediate To Destination
        ADDQ (.B,.W,.L)  #,[]   ADD 1-8 To Destination
        ANDI (.B,.W,.L)  #,[]   AND Immediate To Destination
        ANDI (.B)        #,CCR  AND Immediate To Condition Codes
        ANDI (.B)        #,SR   AND Immediate To Status Register
      # CMPI (.B,.W,.L)  #,[]   CMP Immediate With Destination
        EORI (.B,.W,.L)  #,[]   XOR Immediate With Destination
        EORI (.B)        #,CCR  XOR Immediate To Condition Codes
        EORI (.B)        #,SR   XOR Immediate To Status Register
        ORI  (.B,.W,.L)  #,[]   OR Immediate With Destination
        ORI  (.B)        #,CCR  OR Immediate To Condition Codes
        ORI  (.B)        #,SR   OR Immediate To Status Register
        SUBI (.B,.W,.L)  #,[]   SUB Immediate From Destination
        SUBQ (.B,.W,.L)  #,[]   SUB 1-8 From Destination

   # -- 68020 Added PC Relative Addressing


Single Operand 

        CLR  (.B,.W,.L)   []    Clear Destination
        NEG  (.B,.W,.L)   []    Negate Destination
        NEGX (.B,.W,.L)   []    Negate Dest. With X (Carry)
        NOT  (.B,.W,.L)   []    Complement Destination
      # TST  (.B,.W,.L)   []    Test Destination

   # -- 68020 Added PC Relative Addressing


Shift And Rotate 

        ASR  (.B,.W,.L)   []    Arithmetic Shift Right
        ASL  (.B,.W,.L)   []    Arithmetic Shift Left
        LSR  (.B,.W,.L)   []    Logical Shift Right
        LSL  (.B,.W,.L)   []    Logical Shift Left
        ROR  (.B,.W,.L)   []    Rotate Right
        ROL  (.B,.W,.L)   []    Rotate Left
        ROXR (.B,.W,.L)   []    Rotate Right With X (Carry)
        ROXL (.B,.W,.L)   []    Rotate Left  With X (Carry)

        SWAB (.W)         []    Swap Words


AS.5.7  Bit Manipulation 

        BCHG (.B,.L)    Dn,[]   Test Bit And Change
        BCHG (.B,.L)     #,[]
        BCLR (.B,.L)    Dn,[]   Test A Bit And Clear
        BCLR (.B,.L)     #,[]
        BSET (.B,.L)    Dn,[]   Test A Bit And Set
        BSET (.B,.L)     #,[]
        BTST (.B,.L)    Dn,[]   Test A Bit
        BTST (.B,.L)     #,[]

        Scc  (.B)         []    Set According To Condition
        TAS  (.B)         []    Test And Set An Operand


Branch On Condition Instructions 

   The  short  (.S)  branch instructions have a range of -126 to
+129 bytes relative to the address of  the  branch  instruction.
The  word  (.W)  branch  instructions have a range of -32,766 to
+32,769 bytes relative to the address of the branch instruction.
The instruction argument is normally an address.  

   BCC  label  Carry Clear        BLS  label  Lower Or Same
   BCS  label  Carry Set          BLT  label  Less Than
   BEQ  label  Equal              BMI  label  Minus
   BGE  label  Greater Or Equal   BNE  label  Not Equal
   BGT  label  Greater Than       BPL  label  Plus
   BHI  label  Higher             BVC  label  Overflow Clear
   BLE  label  Less Or Equal      BVS  label  Overflow Set

   BRA  label  Branch Always
   BSR  label  Branch To Subroutine

The  68020 processor supports long (.L) branches to any location
in the 32-bit addressing range.  


Test, Decrement, And Branch Instructions 

   The  Test, Decrement, and Branch instructions support a range
of -32,766 to +32,769 bytes  relative  to  the  address  of  the
branch instruction.  The instruction branch location is normally
an address.  

        DBCC    Dn,label        Carry Clear
        DBLS    Dn,label        Lower Or Same
        DBCS    Dn,label        Carry Set
        DBLT    Dn,label        Less Than
        DBEQ    Dn,label        Equal
        DBMI    Dn,label        Minus
        DBF     Dn,label        False
        DBNE    Dn,label        Not Equal
        DBGE    Dn,label        Greater Or Equal
        DBPL    Dn,label        Plus
        DBGT    Dn,label        Greater Than
        DBT     Dn,label        True
        DBHI    Dn,label        Higher
        DBVC    Dn,label        Overflow Clear
        DBLE    Dn,label        Less Or Equal
        DBVS    Dn,label        Overflow Set


Set According To Condition 

   The Condition is tested and if True the addressed byte is set
to all 1s else the addressed byte is set to all 0s.  

        SCC (.B)  []    Carry Clear
        SLS (.B)  []    Lower Or Same
        SCS (.B)  []    Carry Set
        SLT (.B)  []    Less Than
        SEQ (.B)  []    Equal
        SMI (.B)  []    Minus
        SF  (.B)  []    False
        SNE (.B)  []    Not Equal
        SGE (.B)  []    Greater Or Equal
        SPL (.B)  []    Plus
        SGT (.B)  []    Greater Than
        ST  (.B)  []    True
        SHI (.B)  []    Higher
        SVC (.B)  []    Overflow Clear
        SLE (.B)  []    Less Or Equal
        SVS (.B)  []    Overflow Set


AS.5.11  Bit Field Instructions 

        {} designates {offset:width}

     ** BFCHG   [] {}           Test Bit Field And Change
     ** BFCLR   [] {}           Test Bit Field And Clear
     ** BFEXTS  [] {},Dn        Extract Bit Field Signed
     ** BFEXTU  [] {},Dn        Extract Bit Field Unsigned
     ** BFFFO   [] {},Dn        Find First One In Bit Field
     ** BFINS   Dn,[] {}        Insert Bit Field
     ** BFSET   [] {}           Set Bit Field
     ** BFTST   [] {}           Test Bit Field

  ** -- 68020 Instruction


Trap On Condition 

   The  Condition  is tested and if True the processor initiates
exception processing.  

     ** TRAPCC  (.W,.L) (#)     Carry Clear
     ** TRAPLS  (.W,.L) (#)     Lower Or Same
     ** TRAPCS  (.W,.L) (#)     Carry Set
     ** TRAPLT  (.W,.L) (#)     Less Than
     ** TRAPEQ  (.W,.L) (#)     Equal
     ** TRAPMI  (.W,.L) (#)     Minus
     ** TRAPF   (.W,.L) (#)     False
     ** TRAPNE  (.W,.L) (#)     Not Equal
     ** TRAPGE  (.W,.L) (#)     Greater Or Equal
     ** TRAPPL  (.W,.L) (#)     Plus
     ** TRAPGT  (.W,.L) (#)     Greater Than
     ** TRAPT   (.W,.L) (#)     True
     ** TRAPHI  (.W,.L) (#)     Higher
     ** TRAPVC  (.W,.L) (#)     Overflow Clear
     ** TRAPLE  (.W,.L) (#)     Less Or Equal
     ** TRAPVS  (.W,.L) (#)     Overflow Set

  ** -- 68020 Instruction, .W and .L require #


Other Instructions 

        JMP             []      Jump To Location
        JSR             []      Jump To Subroutine
        LEA  (.L)       [],An   Load Effective Address
        PEA  (.L)       []      Push Effective Address

     ** BKPT            #       Program Break Point
     ** CALLM           #,[]    Call Module
     ** CAS     Du,Dc,[]        Compare And Swap With Operand
     ** CAS2    Dc1:Dc2,Du1:Du2,(Rn1):(Rn2)
      # CHK  (.W)       [],Dn   Check Register Against Bounds
     ** CHK2 (.B,.W,.L) [],Rn   Check Register Against Bounds
     ** CMP2 (.B,.W,.L) [],Rn   Compare Register Against Bounds
      # DIVS.L       [],Dr:Dq   Sgnd Division 64/32 -> 32r:32q
      # DIVSL.L      [],Dr:Dq   Sgnd Division 32/32 -> 32r:32q
      # DIVU.L       [],Dr:Dq   UnSngd Division 64/32 -> 32r:32q
      # DIVUL.L      [],Dr:Dq   UnSngd Division 32/32 -> 32r:32q
        EXG  (.L)       Rn,Rn   Exchange Registers
        EXT  (.W,.L)    Dn      Sign Extend Byte Or Word
     ** EXTB (.L)       Dn      Sign Extend Byte To Long
        ILLEGAL                 Illegal Instruction Exception
      # LINK            An,#    Link And Allocate
      # MULS.L       [],Dl      Signed Multiply 32*32 -> 32
      # MULS.L       [],Dh:Dl   Signed Multiply 32*32 -> 64
      # MULU.L       [],Dl      Unsigned Multiply 32*32 -> 32
      # MULU.L       [],Dh:Dl   Unsigned Multiply 32*32 -> 64
        NOP                     No Operation
     ** PACK    Dx,Dy,#         Pack To BCD
                -(ax),-(ay),#
        RESET                   Reset External Devices
      * RTD             #       Return And Deallocate Parameters
      * RTE                     Return From Exception
     ** RTM             Rn      Return From Module
        RTR                     Return / Restore Condition Codes
        RTS                     Return From Subroutine
        STOP            #       Load Status Register And Stop
        TRAP            #       Trap To Vector (0-15)
        TRAPV                   Trap On Overflow (If Enabled)
        UNLK            An      Load Stack Pointer, Pop Stack

   * -- 68010/68020 Instruction
   # -- 68020 Added Functionality
  ** -- 68020 Instruction

68881/68882 INSTRUCTION SET 

   The  floating  point  instruction set for the 68881 and 68882
coprocessors is summarized in this section.  The 68882  provides
an  increased  level  of performance over the 68881 and is fully
compatible and interchangeable.  

   The coprocessor selection options:  

    .68881 - 68881 Floating Point Processor
    .68882 - 68882 Floating Point Processor

enable  the  assembly  of  the  floating  point instructions and
select the differing execution clock cycles.  The  cycle  counts
are  the worst case values and assume absolutely no overlap with
the main processor or the simultaneous execution of floating in-
structions by the 68882.  

   The  following  sections describe the floating point instruc-
tions separated into these instruction groups:  

        Data Movement
        Dyadic Operations
        Monadic Operations
        Program Control
        System Control


   The  tables contain the operand syntax and the operand format
which is summarized here:  

        FPm     A floating point register (FP0-FP7)
        FPn     A floating point register (FP0-FP7)
        FPcr    A floating point control register
        FPc     Register For Cosine Result
        FPs     Register For Sine Result
        []      Processor addressing mode
        {Dn}    Dynamic packing factor
        {#k}    Static packing factor
        #ccc    ROM constant
        

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Last Updated: September 2023