Section 2 CPU
Rev. 5.00 May 29, 2006 page 20 of 698
REJ09B0146-0500
•
Global Base Register (GBR)
Stores base address of GBR-indirect addressing mode. The GBR-indirect addressing mode is
used for on-chip supporting module register area data transfers and logic operations.
The GBR register can also be accessed in user mode.
Initialized to undefined by a reset.
•
Vector Base Register (VBR)
Stores base address of exception handling vector area.
Initialized to H'0000000 by a reset.
2.2
Data Formats
2.2.1
Data Format in Registers
Register operands are always longwords (32 bits). When a memory operand is only a byte (8 bits)
or a word (16 bits), the sign is extended to the longword, and stores into the register.
Longword
31
0
2.2.2
Data Format in Memory
Memory data formats are classified into bytes, words, and longwords. Memory can be accessed in
8-bit byte, 16-bit word, or 32-bit longword form. A memory operand less than 32 bits in length is
sign-extended before being stored in a register.
A word operand must be accessed starting from a word boundary (even address of a 2-byte unit:
address 2n), and a longword operand starting from a longword boundary (even address of a 4-byte
unit: address 4n). An address error will result if this rule is not observed. A byte operand can be
accessed from any address.
Big-endian or little-endian byte order can be selected for the data format. The endian mode should
be set with the MD5 external pin in a power-on reset. Big-endian mode is selected when the MD5
pin is low, and little-endian when high. The endian mode cannot be changed dynamically. Bit
positions are numbered left to right from most-significant to least-significant. Thus, in a 32-bit
longword, the leftmost bit, bit 31, is the most significant bit and the rightmost bit, bit 0, is the least
significant bit.
Summary of Contents for SH7706 Series
Page 8: ...Rev 5 00 May 29 2006 page viii of xlviii ...
Page 160: ...Section 5 Cache Rev 5 00 May 29 2006 page 112 of 698 REJ09B0146 0500 ...
Page 370: ...Section 11 Watchdog Timer WDT Rev 5 00 May 29 2006 page 322 of 698 REJ09B0146 0500 ...
Page 554: ...Section 17 Pin Function Controller PFC Rev 5 00 May 29 2006 page 506 of 698 REJ09B0146 0500 ...
Page 576: ...Section 18 I O Ports Rev 5 00 May 29 2006 page 528 of 698 REJ09B0146 0500 ...
Page 746: ...Index Rev 5 00 May 29 2006 page 698 of 698 REJ09B0146 0500 ...
Page 749: ...SH7706 Group Hardware Manual ...