H83502 Datasheet, PDF (49/386 Pages) Renesas Technology Corp – single-chip microcomputers

Table 2-6 Bit-Manipulation Instructions (cont)
Instruction
Size* Function
BLD
B
(<bit-No.> of <EAd>) → C
Copies a specified bit in a general register or memory to the C flag.
BILD
¬ (<bit-No.> of <EAd>) → C
Copies the inverse of a specified bit in a general register or memory to
the C flag.
The bit number is specified by 3-bit immediate data.
BST
B
C → (<bit-No.> of <EAd>)
Copies the C flag to a specified bit in a general register or memory.
BIST
¬ C → (<bit-No.> of <EAd>)
Copies the inverse of the C flag to a specified bit in a general register or
memory.
The bit number is specified by 3-bit immediate data.
Note: * Size: operand size
B: Byte
Notes on Bit Manipulation Instructions: BSET, BCLR, BNOT, BST, and BIST are read-
modify-write instructions. They read a byte of data, modify one bit in the byte, then write the byte
back. Care is required when these instructions are applied to registers with write-only bits and to
the I/O port registers.
Order
Read
Modify
Write
Operation
Read one data byte at the specified address
Modify one bit in the data byte
Write the modified data byte back to the specified address
Example: BCLR is executed to clear bit 0 in the port 1 data direction register (P1DDR) under the
following conditions.
P1₇:
Input pin, Low
P1₆:
Input pin, High
P1₅–P1₀: Output pins, Low
The intended purpose of this BCLR instruction is to switch P1₀ from output to input.
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