VHDL Programming

300 Chapter Twelve

Source

Destination

Memory Data
Figure 12-6
Block Copy
Operation.

starting address. This instruction loads register 2 with the destination

address for the block copy. The destination is at 30 hex or 48 decimal.

These load instructions are load-immediate instructions, which load the

next memory location into the register specified in the instruction.

The final setup instruction is at memlocation 04. This instruction loads

the last address of the memory block to be copied. This register signals

the block copy routine when to stop the copy operation. After this instruc-

tion has been executed, all of the registers have been set up for the block

copy operation, and the copy loop can start.

Instruction 6 is the start of a loop of instructions that perform the copy

operation. Instruction 6 copies the contents of the memory location whose

address is contained in register 1 to register 3. Instruction 7 copies the

data in register 3 to the memory location specified in register 2. After