Chapter 8: PCI/G-Bus Bridge
TX7901 User’s Manual (Rev. 6.30T – Nov, 2001)
8-29
8.3.2.4.3 regSwapCtrl
The regSwapCtrl Register controls the Byte Swapper in the data path from the G-Bus to the
PGB registers. The regSwapper cancels the effect of the p2gSwapper when the CPU is in
the Big Endian mode and the p2gSwapper is enabled. Access from the external master on
the PCI Bus to the PGB register is always non-swapped.
Note: When in the Big Endian mode, the regSwapper causes PGB registers to be accessed
by byte swapped data.
63
57
56 55
32
0
reg
Swap
H
0
7
1
24
31
8
7
1
0
0
0
reg
Swap
L
24
7
1
Note: This register is located on the PGB registers. The user must input the same value
into regSwapH and regSwapL. Regardless of whether ByteSwapping is performed or
not, one of these values is written to the regSwap bit.
Table 8-16 regSwapCtrl Register Field Descriptions
Bit(s)
Field
R/W
Description
63:57
-
R/O
Reserved
56
regSwapH
R/W
Same contents as bit 0. (Default is 0 if Little Endian (ie. Big Endian
== 0), 1 if Big Endian == 1.)
55:32
-
R/O
Reserved
31:8
-
R/O
Reserved
7:1
-
R/O
Reserved
0
regSwapL
Swapper in from of the PGB Registers. (Default is 0 if Little Endian
(ie. Big Endian == 0), 1 if Big Endian == 1.)
Note: These bits are the same register, but the position of these bits is changed by the swapper. If
the same value is written to both bit 0 and bit 56, then this same value will be written
regardless of the swapper’s direction.
Summary of Contents for TMPR7901
Page 1: ...TX System RISC TX79 Family TMPR7901 Symmetric 2 way superscalar 64 bit CPU ...
Page 14: ...Handling Precautions ...
Page 15: ......
Page 17: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Page 41: ...4 Precautions and Usage Considerations 4 2 ...
Page 42: ...TX7901 User s Manual Rev 6 30T November 2001 DOCUMENT NUMBER M 99 00004 07 ...
Page 43: ......
Page 259: ...Chapter 13 Removed TX7901 User s Manual Rev 6 30T Nov 2001 13 1 13 Removed ...
Page 260: ...Chapter 13 Removed TX7901 User s Manual Rev 6 30T Nov 2001 13 2 ...