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CHAPTER 3 MEMORY SPACE, CPU AND CONTROL UNIT
3.5
Word Alignment
Instructions and data are accessed in units of bytes. The address structure depends
on the instruction length and data length.
■
Program access
An FR program must be located at an address that is a multiple of 2. Bit 0 of the PC is set to 0
when the PC is updated during instruction execution. Bit 0 of the PC may be set to 1 only when
an odd address is specified as a branch destination address. However, bit 0 is invalid in this
case, and the instruction must be placed at an even address.
There is exception allowing odd addresses.
■
Data access
For data access, the FR series performs the following forcible alignment of addresses in
accordance with the bandwidth for data access:
Word access: Addresses are a multiple of 4 (the lower two bits are forcibly set to 00.)
Half word access: Addresses are a multiple of 2 (the lowest bit is forcibly set to 0.)
Byte access: -
At word or half word data access, some bits are forcibly set to 0 for calculating the effective
address. For example, in the addressing mode of @ (R13, Ri), the register value before addition
is used for calculation (even if the LSB is 1) and the lower bits of the addition result are masked.
R13 00002222
H
R2 00000003
H
+ )
00002225
H
[Example] LD @ (R13, R2), R0
Addition result
Lower two bits forcibly masked
Address pin
00002224
H
Summary of Contents for MB91150 Series
Page 1: ......
Page 2: ......
Page 3: ...FUJITSU LIMITED FR30 32 BIT MICROCONTROLLER MB91150 Series HARDWARE MANUAL ...
Page 4: ......
Page 10: ...vi ...
Page 112: ...96 CHAPTER 3 MEMORY SPACE CPU AND CONTROL UNIT ...
Page 178: ...162 CHAPTER 5 I O PORTS ...
Page 214: ...198 CHAPTER 7 16 BIT RELOAD TIMER ...
Page 240: ...224 CHAPTER 8 PPG TIMER ...
Page 310: ...294 CHAPTER 13 8 10 BIT A D CONVERTER ...
Page 318: ...302 CHAPTER 14 8 BIT D A CONVERTER ...
Page 362: ...346 CHAPTER 15 UART ...
Page 420: ...404 CHAPTER 19 PERIPHERAL STOP CONTROL ...
Page 428: ...412 CHAPTER 20 CALENDAR MACROS ...
Page 503: ...487 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 510: ...494 INDEX ...
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