Epson CMOS 32-Bit Single Chip Microcomputer S1C33L03 Instrukcja Użytkownika Pobierz pdf (Strona 44)

5 INSTRUCTION SET

EPSON

S1C33 FAMILY C33 PE CORE MANUAL

5.12 Bit Manipulation Instructions

The following four instructions are provided for manipulating the data in memory bitwise or one bit at a time.

These instructions allow the display memory or I/O map control bits to be altered directly.

btst [%rb],imm3 Set the Z flag if a specified bit = 0

bclr [%rb],imm3 Clear a specified bit to 0

bset [%rb],imm3 Set a specified bit to 1

bnot [%rb],imm3 Invert a specified bit (1 ↔ 0)

Bit manipulation is performed on the memory address specified by the rb (general-purpose) register. imm3 specifies

a bit number (bits 0–7) in the byte data stored in that address location.

Although the content of memory data altered by these instructions (except btst) is only the specified bit, the

specified address is rewritten because memory is accessed bytewise. Therefore, if the addresses to be manipulated

have any I/O control bits mapped whose function is enabled by a bit write operation, use of these instructions

requires caution.

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Epson CMOS 32-Bit Single Chip Microcomputer S1C33L03 Instrukcja Użytkownika Strona 44