UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 90

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

3.7 CONTROL REGISTERS
3.7.1 Program Counter (PC)
associated with a branch is executed, the immediate data or register contents are set in the PC.
PC.
3.7.2 Program Status Word (PSW)
instruction execution.
flags can be manipulated by bit-manipulation instructions.
instruction is executed, and automatically restored when an RETI or RETB instruction is executed. When context switching is
used, the contents are automatically saved in RP3, and automatically restored when an RETCS or RETCSB instruction is
executed.
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Control registers consist of the program counter (PC), program status word (PSW), and stack pointer (SP).
This is a 20-bit binary counter that holds address information on the next program to be executed (see Figure 3-7).
Normally, the PC is incremented automatically by the number of bytes in the fetched instruction. When an instruction
Upon RESET input, the 16-bit data in address 0 and 1 is set in the low-order 16 bits, and 0000 in the high-order 4 bits of the
The program status word (PSW) is a 16-bit register comprising various flags that are set or reset according to the result of
Read accesses and write accesses are performed in high-order 8-bit (PSWH) and low-order 8-bit (PSWL) units. Individual
The contents of the PSW are automatically saved to the stack when a vectored interrupt request is acknowledged or a BRK
RESET input resets (0) all bits.
“0” must always be written to the bits written as “0” in Figure 3-8. The contents of bits written as “-” are undefined when read.
PC
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Figure 3-7 Program Counter (PC) Format
CHAPTER 3 CPU ARCHITECTURE
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