360 Assembly/360 Instructions/LGR
LGR - Load Register - 64 Bit - Opcode B904 - RRE Instruction
Format
[edit | edit source]- LGR 2,6
The specific syntax is
- LGR target register, source register.
| RRE Instruction (4 bytes) | |||
| Bytes 1 and 2 | Byte 3 | Byte 4 | |
| target register | source register | ||
| (16 bits) Opcode B904 |
(8 bits) Not used |
(4 bits) 0..F |
(4 bits) 0..F |
- The first argument is a target register which value is affected by the instruction.
- The second argument is the source value register.
Availability
[edit | edit source]The LGR instruction is 64-bit, and is only available on the 370 series and z/System. It will cause an opcode exception on the 360 series.
Operation
[edit | edit source]The LGR instruction copies a 64-bit value from the register specified by the second argument to the register specified by the first argument.
Condition codes are not changed.
Register 0 is valid for either register and is not ignored as in some other instructions.
Exceptions and Faults
[edit | edit source]- 360 Series: Opcode Exception
- 370 Series and zSystem: None.
Most Closely-related Instruction
[edit source]The most closely-related instruction is Add Logical Register (ALR) and not Load Address (LA), as is sometimes assumed. Whereas L loads a value from memory, LA does not access memory; it only calculates a number, which can but does not have to be an address.
32-Bit Instructions
[edit source]- To load an 8-bit byte (character) value from memory, see IC.
- To load one or more 8-bit byte values into a register according to a mask, see ICM
- To load a 16-bit half-word value from memory, see LH.
- To load a 12-bit unsigned value into a register or add up to 4095 to the values in one or two 32-bit registers, see LA.
- To copy a 32-bit word value from one register to another register, see LR.
- To load a 32-bit word value from memory, see L.
- To store an 8-bit byte (character) value in memory, see STC.
- To store one or more 8-bit byte values into memory according to a mask, see STCM
- To store a 16-bit half-word value in memory, see STH.
- To store a 32-bit word value in memory, see ST.
64-Bit Instructions
[edit source]- To load a 20-bit signed value into a 32-bit or 64-bit register from an extended (20-bit) signed memory offset, see LAY.
- To load a 32-bit value into a 64-bit register from an extended (20-bit) signed memory offset, see LGF.
- To copy a 64-bit value from one 64-bit register to another 64-bit register, see LGR.
- To load a 64-bit value into a 64-bit register from memory, see LG.
- To store a 32-bit value from a register to an extended (20-bit) signed memory offset, see STY.
- To store a 64-bit value from a 64-bit register to an address in memory, see STG.
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