CHAPTER 3 CPU INSTRUCTION SET SUMMARY
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Table 3-2. Load/store Instruction
Instruction
Format and Description
Load Byte
LB rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The bytes of the memory location specified by the address are sign extended and loaded into register rt.
Load Byte Unsigned
LBU rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The bytes of the memory location specified by the address are zero extended and loaded into register rt.
Load Halfword
LH rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The halfword of the memory location specified by the address is sign extended and loaded to register rt.
Load Halfword
Unsigned
LHU rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The halfword of the memory location specified by the address is zero extended and loaded to register rt.
Load Word
LW rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The word of the memory location specified by the address is sign extended and loaded to register rt. In the
64-bit mode, it is further sign extended to 64 bits.
Load Word Left
LWL rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
Shifts to the left the word whose address is specified so that the address-specified byte is at the left-
most position of the word. The result of the shift operation is merged with the contents of register rt
and loaded to register rt. In the 64-bit mode, it is further sign extended to 64 bits.
Load Word Right
LWR rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
Shifts to the right the word whose address is specified so that the address-specified byte is at the right-
most position of the word. The result of the shift operation is merged with the contents of register rt and
loaded to register rt. In the 64-bit mode, it is further sign extended to 64 bits.
Store Byte
SB rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The least significant byte of register rt is stored to the memory location specified by the address.
Store Halfword
SH rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The least significant halfword of register rt is stored to the memory location specified by the address.
Store Word
SW rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
The lower word of register rt is stored to the memory location specified by the address.
Store Word Left
SWL rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
Shifts to the right the contents of register rt so that the left-most byte of the word is in the position of the
address-specified byte. The result is stored to the lower word in memory.
Store Word Right
SWR rt, offset (base)
The offset is sign extended and then added to the contents of the register base to form the virtual address.
Shifts to the left the contents of register rt so that the right-most byte of the word is in the position of the
address-specified byte. The result is stored to the upper word in memory.
op
base
rt
offset