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Level Two Interface

8.5Data Read/Write Interface transfers

The tables in this section describe the AXI interface behavior for Data Read/Write Interface transfers for the following interface signals:

AxBURSTRW[1:0]

AxLENRW[3:0]

AxSIZERW[2:0]

AxADDRRW[31:0]

WSTRBRW[7:0].

8.5.1Linefills

A linefill comprises four accesses to the Data Cache if there is no external abort returned. In the event of an external abort, the doubleword and subsequent doublewords are not written into the Data Cache and the line is never marked as Valid. The four accesses are:

Write Tag and data doubleword

Write data doubleword

Write data doubleword

Write Valid = 1, Dirty = 0, and data doubleword.

The linefill can only progress to attempt to write a doubleword if it does not contain dirty data. This is determined in one of two ways:

if the victim cache line is not valid, then there is no danger and the linefill progresses

if the victim line is valid, a signal encodes the doublewords that are clean, either because they were not dirty or they have been cleaned.

The order of words written into the cache is critical-word first, wrapping at the upper cache line boundary.

Table 8-12 shows the values of ARADDRRW, ARBURSTRW, ARSIZERW, and

ARLENRW for linefills.

Table 8-12 Linefill behavior on the AXI interface

Address[4:0]

ARADDRRW

ARBURSTRW

ARSIZERW

ARLENRW

 

 

 

 

 

0x00 -0x07

0x00

Incr

64-bit

4 data transfers

 

 

 

 

 

0x08-0x0F

0x08

Wrap

64-bit

4 data transfers

 

 

 

 

 

0x10-0x17

0x10

Wrap

64-bit

4 data transfers

 

 

 

 

 

0x18-0x1F

0x18

Wrap

64-bit

4 data transfers

 

 

 

 

 

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8.5.2Noncacheable LDRB

Table 8-13 shows the values of ARADDRRW, ARBURSTRW, ARSIZERW, and

ARLENRW for Noncacheable LDRBs from bytes 0-7.

Table 8-13 Noncacheable LDRB

Address[4:0]

ARADDRRW

ARBURSTRW

ARSIZERW

ARLENRW

 

 

 

 

 

0x00, byte 0

0x00

Incr

8-bit

1 data transfer

 

 

 

 

 

0x01, byte 1

0x01

Incr

8-bit

1 data transfer

 

 

 

 

 

0x02, byte 2

0x02

Incr

8-bit

1 data transfer

 

 

 

 

 

0x03, byte 3

0x03

Incr

8-bit

1 data transfer

 

 

 

 

 

0x04, byte 4

0x04

Incr

8-bit

1 data transfer

 

 

 

 

 

0x05, byte 5

0x05

Incr

8-bit

1 data transfer

 

 

 

 

 

0x06, byte 6

0x06

Incr

8-bit

1 data transfer

 

 

 

 

 

0x07, byte 7

0x07

Incr

8-bit

1 data transfer

 

 

 

 

 

8.5.3Noncacheable LDRH

Table 8-14 shows the values of ARADDRRW, ARBURSTRW, ARSIZERW, and

ARLENRW for Noncacheable LDRHs from bytes 0-7.

Table 8-14 Noncacheable LDRH

Address[4:0]

ARADDRRW

ARBURSTRW

ARSIZERW

ARLENRW

 

 

 

 

 

0x00, byte 0

0x00

Incr

16-bit

1 data transfer

 

 

 

 

 

0x01, byte 1

0x01

Incr

32-bit

1 data transfer

 

 

 

 

 

0x02, byte 2

0x02

Incr

16-bit

1 data transfer

 

 

 

 

 

0x03, byte 3

0x03

Incr

8-bit

1 data transfer

 

 

 

 

 

 

0x04

Incr

8-bit

1 data transfer

 

 

 

 

 

0x04, byte 4

0x04

Incr

16-bit

1 data transfer

 

 

 

 

 

0x05, byte 5

0x05

Incr

32-bit

1 data transfer

 

 

 

 

 

0x06, byte 6

0x06

Incr

16-bit

1 data transfer

 

 

 

 

 

0x07, byte 7

0x07

Incr

8-bit

1 data transfer

 

 

 

 

 

 

0x08

Incr

8-bit

1 data transfer

 

 

 

 

 

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8.5.4Noncacheable LDR or LDM1

Table 8-15 shows the values of ARADDRRW, ARBURSTRW, ARSIZERW, and

ARLENRW for Noncacheable LDRs or LDM1s.

Table 8-15 Noncacheable LDR or LDM1

Address[4:0]

ARADDRRW

ARBURSTRW

ARSIZERW

ARLENRW

 

 

 

 

 

0x00, byte 0, word 0

0x00

Incr

32-bit

1 data transfer

 

 

 

 

 

0x01, byte 1

0x01

Incr

32-bit

1 data transfer

 

 

 

 

 

 

0x04

Incr

8-bit

1 data transfer

 

 

 

 

 

0x02, byte 2

0x02

Incr

16-bit

1 data transfer

 

 

 

 

 

 

0x04

Incr

16-bit

1 data transfer

 

 

 

 

 

0x03, byte 3

0x03

Incr

8-bit

1 data transfer

 

 

 

 

 

 

0x04

Incr

32-bit

1 data transfer

 

 

 

 

 

0x04, byte 4, word 1

0x04

Incr

32-bit

1 data transfer

 

 

 

 

 

0x05, byte 5

0x05

Incr

32-bit

1 data transfer

 

 

 

 

 

 

0x08

Incr

8-bit

1 data transfer

 

 

 

 

 

0x06, byte 6

0x06

Incr

16-bit

1 data transfer

 

 

 

 

 

 

0x08

Incr

16-bit

1 data transfer

 

 

 

 

 

0x07, byte 7

0x07

Incr

8-bit

1 data transfer

 

 

 

 

 

 

0x08

Incr

32-bit

1 data transfer

 

 

 

 

 

8.5.5Noncacheable LDRD or LDM2

Table 8-16 shows the values of ARADDRRW, ARBURSTRW, ARSIZERW, and

ARLENRW for Noncacheable LDRDs or LDM2s addressing words 0 to 6.

A Noncacheable LDRD or LDM2 addressing word 7 is split into two LDRs, as shown in

Table 8-17 on page 8-18.

Table 8-16 Noncacheable LDRD or LDM2

Address[4:0]

ARADDRRW

ARBURSTRW

ARSIZERW

ARLENRW

 

 

 

 

 

0x00, word 0

0x00

Incr

64-bit

1 data transfer

 

 

 

 

 

0x04, word 1

0x04

Incr

32-bit

2 data transfers

 

 

 

 

 

0x08, word 2

0x08

Incr

64-bit

1 data transfer

 

 

 

 

 

0x0C, word 3

0x0C

Incr

32-bit

2 data transfers

 

 

 

 

 

0x10, word 4

0x10

Incr

64-bit

1 data transfer

 

 

 

 

 

0x14, word 5

0x14

Incr

32-bit

2 data transfers

 

 

 

 

 

0x18, word 6

0x18

Incr

64-bit

1 data transfer

 

 

 

 

 

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Table 8-17 Noncacheable LDRD or LDM2 from word 7

Address[4:0] Operations

0x1C, word 7 LDR from 0x1C + LDR from 0x00

8.5.6Noncacheable LDM3

The values of ARADDRRW, ARBURSTRW, ARSIZERW, and ARLENRW for

Noncacheable LDM3s addressing words 0 to 5 are shown in:

Table 8-18 for a load from Strongly Ordered or Device memory

Table 8-19 for a load from Noncacheable memory or when the cache is disabled.

A Noncacheable LDM3 addressing word 6 or 7 is split into two operations as shown in

Table 8-20.

Table 8-18 Noncacheable LDM3, Strongly Ordered or Device memory

Address[4:0]

ARADDRRW

ARBURSTRW

ARSIZERW

ARLENRW

 

 

 

 

 

0x00, word 0

0x00

Incr

32-bit

3 data transfers

 

 

 

 

 

0x04, word 1

0x04

Incr

32-bit

3 data transfers

 

 

 

 

 

0x08, word 2

0x08

Incr

32-bit

3 data transfers

 

 

 

 

 

0x0C, word 3

0x0C

Incr

32-bit

3 data transfers

 

 

 

 

 

0x10, word 4

0x10

Incr

32-bit

3 data transfers

 

 

 

 

 

0x14, word 5

0x14

Incr

32-bit

3 data transfers

 

 

 

 

 

Table 8-19 Noncacheable LDM3, Noncacheable memory or cache disabled

Address[4:0]

ARADDRRW

ARBURSTRW

ARSIZERW

ARLENRW

 

 

 

 

 

0x00, word 0

0x00

Incr

64-bit

2 data transfers

 

 

 

 

 

0x04, word 1

0x04

Incr

64-bit

2 data transfers

 

 

 

 

 

0x08, word 2

0x08

Incr

64-bit

2 data transfers

 

 

 

 

 

0x0C, word 3

0x0C

Incr

64-bit

2 data transfers

 

 

 

 

 

0x10, word 4

0x10

Incr

64-bit

2 data transfers

 

 

 

 

 

0x14, word 5

0x14

Incr

64-bit

2 data transfers

 

 

 

 

 

Table 8-20 Noncacheable LDM3 from word 6, or 7

Address[4:0] Operations

0x18, word 6 LDM2 from 0x18 + LDR from 0x00

0x1C, word 7 LDR from 0x1C + LDM2 from 0x00

8.5.7Noncacheable LDM4

The values of ARADDRRW, ARBURSTRW, ARSIZERW, and ARLENRW for

Noncacheable LDM4s addressing words 0 to 4 are shown in:

Table 8-21 on page 8-19 for a load from Strongly Ordered or Device memory

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