- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄365371 > PowerPC 603 (Motorola, Inc.) 32-Bit Microprocessor(32位微處理器) PDF資料下載
參數(shù)資料
| 型號： | PowerPC 603 |
| 廠商： | Motorola, Inc. |
| 英文描述： | 32-Bit Microprocessor(32位微處理器) |
| 中文描述： | 32位微處理器（32位微處理器） |
| 文件頁數(shù)： | 52/54頁 |
| 文件大?。?/td> | 325K |
| 代理商： | POWERPC 603 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁當(dāng)前第52頁第53頁第54頁
RISC Microprocessor Division
Page 52
The mix of instructions in an instruction sequence can result in a variety of stalls. Dependency stalls
are the most common. A dependency occurs if one instruction uses as its source data the results from
another instruction. Such a dependency will cause a stall if the two instructions are placed right next to
each other. The 603e reduces the impact of most of these situations through use of the rename
registers and forwarding of results. However, in some situations, stalls can happen as follows.
Two orderings of a code sequences are shown. In both sequences, the
add
instruction uses as its
source the results of the
lwzx
load instruction. In the original code, the
add
occurs right after the
lwzx
. In the reordered sequence, the
add
is separated from the
lwzx
by moving it down three
instructions.
Analysis of original code sequence:
Assuming the
lwzx
hits in the data cache, its data will return in 2 clocks. Although both the
add
and
the
lwzx
can be dispatched to the completion queue in the same clock, the
add
cannot begin
execution until the data from the
lwzx
returns. Therefore it cannot retire with the
lwzx
and is stalled
by one clock. The
lis
dispatches to the SRU, executes, and is ready to retire with the
add
in cycle 3.
In cycle 4, the
stwu
and
ori
can also retire together. Then in cycle 5, the
cmpw
retires alone. Total
time: 5 clocks.
Analysis of reordered code sequence:
The
lwzx
(cache hit) takes 2 clocks. Since the
lis
is not dependent on the
lwzx
, it can retire with the
lwzx
in clock 2. The
stwu
and
ori
can also retire together on the next clock (clock 3). Finally, in
clock 4, the
add
and
cmpw
retire together. Total time: 4 clocks.
Thus by separating the generation of a result from the subsequent use of that result, we were able to
prevent a stall. It is normally a good practice to provide this separation; however in some cases the
benefit gained in one place is lost in another place.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| PowerPC 604e | 32-Bit Microprocessor(32位微處理器) |
| PowerPC 604 | 32-Bit Microprocessor(32位微處理器) |
| PPC7447RX1000NB | PPC7457RX1000NB |
| PPC7447RX867NB | PPC7457RX1000NB |
| PPC7457RX1000NB | PPC7457RX1000NB |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| POWERPLUG15W | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:AC/DC POWER SUPPLY |
| POWERPLUG24W | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:AC/DC POWER SUPPLY |
| POWERPLUS 2C 2500MAH | 制造商:Energizer Battery Company 功能描述: |
| POWERPLUS 2D 2500MAH | 制造商:Energizer Battery Company 功能描述: |
| POWERPLUS 4AAA 850MAH | 制造商:Energizer Battery Company 功能描述: |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。