Topic       : MC56001 Documentation
Author      : JAY Software
Version     : 1.0 (19/11/1997)
Subject     : Programming/Assembler
Nodes       : 152
Index Size  : 4106
HCP-Version : 4
Compiled on : Atari
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View Ref-FileORI                     OR Immediate with Control Register

Operation:
    #xx + D -> D
    where + denotes the logical inclusive OR operator

Assembler Syntax:
    OR(I)   #xx,D

Description:
    Logically OR the 8-bit immediate operand (#xx) with the contents
of the destination control register D and store the result in the
destination control register. The condition code are affected only when
the condition code register (CCR) is specified as the destination
operand.

Restrictions:
    The ORI #xx,MR instruction cannot be used immediately before an
ENDDO or RTI instruction and cannot be one of the last three
instructions in a DO loop (at LA-2, LA-1, or LA).

    Example:
    ORI #$8,MR      ;set scaling mode bit S1 to scale up

Before Execution:
    MR = $03
After Execution:
    MR = $0B

Explanation of Example:
    Prior to execution, the 8-bit mode register (MR)
contains the value $03. The ORI #$8,MR instruction logically ORs
the immediate 8-bit value $8 with the contents of the
mode register and stores the result in the mode register.

Condition Codes:

     15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |LF|**| T|**|S1|S0|I1|I0|**| L| E| U| N| Z| V| C|
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |<-           MR         ->|<-       CCR      ->|

    For CCR Operand:
    L- Set if bit 6 of the immediate operand is cleared
    E- Set if bit 5 of the immediate operand is cleared
    U- Set if bit 4 of the immediate operand is cleared
    N- Set if bit 3 of the immediate operand is cleared
    Z- Set if bit 2 of the immediate operand is cleared
    V- Set if bit 1 of the immediate operand is cleared
    C- Set if bit 0 of the immediate operand is cleared

    For MR and OMR Operands:
    The condition codes are not affected using these operands.

Instruction Format:
    ORI #xx,D

    D = (MR,CCR,OMR)

Timing:     2 oscillator clock cycles

Memory:     1 program word