LOADR

Description

Loads a value from memory into the destination register. The address used is the summation of the second and third operand registers. The contents of the second and third registers are treated as unsigned 4-byte aligned numbers. The final nibble of the instruction is a byte mask used to set which bytes are actually loaded from memory and which are discarded.

Register Access

The LOADR instruction can use any of the general purpose registers R0 to R15 as either destination or source operands.

Memory Layout

This is a 3 byte instruction

Opcode  | Condition Code |  Destination | Source 1 | Source 2 | Bit Mask
000001  |       00       |     DDDD     | RRRR     | rrrr     | bbbb

Assembly Code Examples

Note that the final byte mask is optional. If it is omitted (as in example 3) then it is assumed to be 1111. It should be 4 characters long and only '1' or '0'.

1. | LOAD $R0 $R1 $R3    1111 ; Load all bits into R0
2. | LOAD $R7 $R14 $R13  1100 ; Load the upper 16 bits into R7
3. | LOAD $R5 $R5 $R6         ; Replace R5 with the memory contents.

See Also

Instructions Quick Reference, LOADI

---