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Syntax: reg = DM ( <addr> ) ;
Permissible registers
AX0 MX0 SI SB CNTR
AX1 MX1 SE PX OWRCNTR (write only)
AY0 MY0 SR1 ASTAT RX0
AY1 MY1 SR0 MSTAT RX1
AR MR2 I0-I7 TX0
MR1 M0-M7 IMASK TX1
MR0 L0-L7 ICNTL IFC(write only)
Example: SI = DM( ad_port0 );
Description: The Read instruction moves the contents of the data
memory location to the destination register. The addressing mode is direct
addressing (designated by an immediate address value or by a label). The
data memory address is stored directly in the instruction word as a full 14-
bit field. The contents of the source are always right-justified in the
destination register after the read (bit 0 maps to bit 0).
Note that whenever MR1 is loaded with data, it is sign-extended into
MR2.
Status Generated: None affected.
Instruction Format:
Data Memory Read (Direct Address), Instruction Type 3:
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 0 0 0 RGP ADDR REG
ADDR contains the direct address to the source location in Data Memory.
RGP (Register Group) and REG (Register) select the destination register
according to the Register Selection Table (see Appendix A).
MOVE
DATA MEMORY READ (Direct Address)
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