SH7021 datasheet(41/509 Pages) RENESAS

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cycles.

T bit: T bit (in the status register) is set according to the result of a comparison, and in turn is the

condition (True/False) that determines if the program will branch. The T bit in the status register is

only changed by selected instructions, thus improving the processing speed.

Table 2.4

T bit

CPU of SH7000 Series

Description

Conventional CPU

CMP/GE R1, R0

TRGET0

TRGET1

T bit is set when R0

≥ R1. The program

branches to TRGET0 when R0

≥ R1

and to TRGET1 when R0<R1.

CMP.W

R1, R0

BGE

TRGET0

BLT

TRGET1

ADD

#–1, R0

TST

R0, R0

TRGET

T bit is not changed by ADD. T bit is set

when R0=0. The program branches if

R0=0.

SUB.W

#1, R0

BEQ

TRGET

Immediate Data: Byte (8-bit) immediate data is located in the instruction code. Word or long

word immediate data is not located in instruction codes but is stored in a memory table. The

memory table is accessed by a immediate data transfer instruction (MOV) using the PC relative

addressing mode with displacement.

Table 2.5

Immediate Data Accessing

Classification

CPU of SH7000 Series

Conventional CPU

8-bit immediate

MOV

#H'12, R0

MOV.B

#H'12, R0

16-bit immediate

MOV.W

@(disp,PC), R0

.........

.DATA.W

H'1234

MOV.W

#H'1234, R0

32-bit immediate

MOV.L

@(disp,PC), R0

.........

.DATA.L

H'12345678

MOV.L

#H'12345678, R0

Note:

The address of the immediate data is accessed by @(disp, PC).

Absolute Address: When data is accessed by absolute address, the value already in the absolute

address is placed in the memory table. By loading the immediate data when the instruction is

executed, that value is transferred to the register and the data is accessed in the indirect register

addressing mode.

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