IBM PowerPC 604 User Manual page 86

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• Load and store instructions-These include integer and floating-point load and store
instructions. For more information, see Section 2.3.4.3, "Load and Store
Instructions."
• Flow control instructions-These include branching instructions, condition register
logical instructions, trap instructions, and other instructions that affect the
instruction flow. For more information, see Section 2.3.4.4, "Branch and Flow
Control Instructions."
• Processor control instructions-These instructions are used for synchronizing
memory accesses and managing caches, TLBs, and segment registers. For more
information, see Section 2.3.4.6, "Processor Control Instructions-VISA,"
Section 2.3.5.1, "Processor Control Instructions-VEA," and Section 2.3.6.2,
"Processor Control Instructions-OBA."
• Memory synchronization instructions-These instructions are used for memory
synchronizing. See Section 2.3.4.7, "Memory Synchronization
Instructions-VISA," Section 2.3.5.2, "Memory Synchronization
Instructions-VEA," for more information.
• Memory control instructions-These instructions provide control of caches, TLBs,
and segment registers. For more information, see Section 2.3.5.3, "Memory Control
Instructions-VEA," and Section 2.3.6.3, "Memory Control Instructions-OBA."
• External control instructions-These include instructions for use with special
input/output devices. For more information, see Section 2.3.5.4, "Optional External
Control Instructions."
Note that this grouping of instructions does not necessarily indicate the execution unit that
processes a particular instruction or group of instructions. This information, which is useful
in taking full advantage of the 604 's superscalar parallel instruction execution, is provided
in Chapter 6, "Instruction Timing."
Integer instructions operate on word operands. Floating-point instructions operate on
single-precision and double-precision floating-point operands. The PowerPC architecture
uses instructions that are four bytes long and word-aligned. It provides for byte, half-word,
and word operand loads and stores between memory and a set of 32 general-purpose
registers (GPRs). It also provides for word and double-word operand loads and stores
between memory and a set of 32 floating-point registers (FPRs).
Arithmetic and logical instructions do not read or modify memory. To use the contents of a
memory location in a computation and then modify the same or another memory location,
the memory contents must be loaded into a register, modified, and then written to the target
location using load and store instructions.
The description of each instruction includes the mnemonic and a formatted list of operands.
To simplify assembly language programming, a set of simplified mnemonics and symbols
is provided for some of the frequently-used instructions; see Appendix F, "Simplified
Mnemonics," in
The Programming Environments Manual
for a complete list of simplified
2-20 PowerPC 604 RISC Microprocessor User's Manual