45
CHAPTER 2 CPU
2.8
Register Bank
A register bank consists of eight words. The register bank can be used as the following
general-purpose registers for arithmetic operations: byte registers R0 to R7, word
registers RW0 to RW7, and long word registers RL0 to RL3. In addition, the register
bank can be used as instruction pointers.
■
Register Bank
Table 2.8-1 lists the functions of the registers. Table 2.8-2 indicates the relationship between the registers.
In the same manner as for an ordinary RAM area, the register bank values are not initialized by a reset. The
status before a reset is maintained. When the power is turned on, however, the register bank will have an
undefined value.
Table 2.8-1 Register Functions
R0 to R7
Used as operands of instructions.
Note: R0 is also used as a counter for barrel shift or normalization instructions.
RW0 to RW7
Used as pointers.
Used as operands of instructions.
Note: RW0 is used as a counter for string instructions.
RL0 to RL3
Used as long pointers.
Used as operands of instructions.
Table 2.8-2 Relationship between Registers
RW0
RL0
RW1
RW2
RL1
RW3
R0
RW4
RL2
R1
R2
RW5
R3
R4
RW6
RL3
R5
R6
RW7
R7
Summary of Contents for MB90390 Series
Page 2: ......
Page 4: ......
Page 17: ...xiii APPENDIX D List of Interrupt Vectors 690 INDEX 695 ...
Page 18: ...xiv ...
Page 132: ...104 CHAPTER 5 CLOCKS ...
Page 152: ...124 CHAPTER 6 CLOCK MODULATOR ...
Page 210: ...182 CHAPTER 11 TIME BASE TIMER ...
Page 218: ...190 CHAPTER 12 WATCHDOG TIMER ...
Page 264: ...236 CHAPTER 14 16 BIT RELOAD TIMER WITH EVENT COUNT FUNCTION ...
Page 274: ...246 CHAPTER 15 WATCH TIMER ...
Page 306: ...278 CHAPTER 17 DTP EXTERNAL INTERRUPTS ...
Page 338: ...310 CHAPTER 18 8 10 BIT A D CONVERTER ...
Page 364: ...336 CHAPTER 19 UART0 UART1 ...
Page 398: ...370 CHAPTER 20 UART2 UART3 Figure 20 5 2 ORE Set Timing Receive data RDRF ORE ...
Page 432: ...404 CHAPTER 20 UART2 UART3 ...
Page 482: ...454 CHAPTER 22 SERIAL I O ...
Page 560: ...532 CHAPTER 24 STEPPING MOTOR CONTROLLER ...
Page 582: ...554 CHAPTER 27 ROM MIRRORING MODULE ...
Page 632: ...604 CHAPTER 29 EXAMPLES OF SERIAL PROGRAMMING CONNECTION ...
Page 722: ...694 APPENDIX ...
Page 723: ...695 INDEX The index follows on the next page This is listed in alphabetic order ...
Page 740: ......