SH7751 Datasheet, PDF (906/1224 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

20. User Break Controller (UBC)
20.3 Operation
20.3.1 Explanation of Terms Relating to Accesses
An instruction access is an access that obtains an instruction. For example, the fetching of an
instruction from the branch destination when a branch instruction is executed is an instruction
access. An operand access is any memory access for the purpose of instruction execution. For
example, the access to address PC+disp×2+4 in the instruction MOV.W@(disp,PC), Rn is an
operand access. As the term “data” is used to distinguish data from an address, the term “operand
access” is used in this section.
In this LSI, all operand accesses are treated as either read accesses or write accesses. The
following instructions require special attention:
• PREF, OCBP, and OCBWB instructions: Treated as read accesses.
• MOVCA.L and OCBI instructions: Treated as write accesses.
• TAS.B instruction: Treated as one read access and one write access.
The operand accesses for the PREF, OCBP, OCBWB, and OCBI instructions are accesses with no
access data.
This LSI handles all operand accesses as having a data size. The data size can be byte, word,
longword, or quadword. The operand data size for the PREF, OCBP, OCBWB, MOVCA.L, and
OCBI instructions is treated as longword.
20.3.2 Explanation of Terms Relating to Instruction Intervals
In this section, “1 (2, 3, ...) instruction(s) after...”, as a measure of the distance between two
instructions, is defined as follows. A branch is counted as an interval of two instructions.
• Example of sequence of instructions with no branch:
100 Instruction A (0 instructions after instruction A)
102 Instruction B (1 instruction after instruction A)
104 Instruction C (2 instructions after instruction A)
106 Instruction D (3 instructions after instruction A)
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