- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄360867 > INSTRUCTIN603EWP Optimizing the Instruction Execution on the 603e PDF資料下載
參數(shù)資料
| 型號： | INSTRUCTIN603EWP |
| 英文描述： | Optimizing the Instruction Execution on the 603e |
| 中文描述： | 優(yōu)化了603e的指令執(zhí)行 |
| 文件頁數(shù)： | 21/54頁 |
| 文件大小： | 325K |
| 代理商： | INSTRUCTIN603EWP |
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頁當(dāng)前第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頁第52頁第53頁第54頁
RISC Microprocessor Division
Page 21
In this slide, we depict a potential stall that can occur with branches. The code fragments demonstrate
how, in some cases, one can use branches that are foldable to attain better performance than using
non-foldable branches.
The two loops repeat for COUNT iterations. The first code fragment initializes the CTR and uses only
one instruction to control the looping,
bdnz
. (
bdnz
is a simplified mnemonic for a conditional branch
which decrements the CTR and branches if CTR is not zero.) This branch cannot be folded and must
be dispatched. Since branches that dispatch are required to retire from the last stage of the completion
unit, any loop involving a branch that dispatches may need an extra clock (in addition to the loop body
time) to complete execution.
It is possible to avoid the additional latency by using a foldable branch instead of the
bdnz
. The
bgt
and the
subi.
instructions in the second code fragment can be used to obtain the same functionality
as the
bdnz
. The
subi.
instruction is a single cycle instruction that can retire paired with almost any
other instruction; thus in most loops,
subi.
adds no time to the execution of that loop. The
bgt
is also
capable of being folded out of the pipeline and not dispatching at all. Therefore, code that uses the
subi.
/
bgt
combination will likely be a clock faster each time through the loop then
bdnz
. However,
the exact timing difference, if any, would depend on the actual composition of the loop body.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| INT201PFI1 | Interface IC |
| INT201TFI1 | Interface IC |
| INT2404G | LED BACKLIGHT FOR LCD DISPLAY |
| INT4003G | LED BACKLIGHT FOR LCD DISPLAY |
| INTEGRA | Integra L64754 ISDB-S DVB/DSS Satellite Receiver |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| INSUL 2 DB-52P | 制造商:ITT 功能描述:MICRO 制造商:ITT Interconnect Solutions 功能描述:MICRO |
| INSUL 2 DE 19 SKT DOUBLE | 制造商:ITT 功能描述:MICRO 制造商:ITT Interconnect Solutions 功能描述:MICRO |
| INSUL 2 DE-19 PIN DBL DEN | 制造商:ITT 功能描述:MICRO 制造商:ITT Interconnect Solutions 功能描述:MICRO |
| INSUL ASSY CV3450-36-6 PIN | 制造商:ITT 功能描述:Circular 制造商:ITT Interconnect Solutions 功能描述:Circular |
| INSUL ASSY CV-R 36-10 PIN | 制造商:ITT Interconnect Solutions 功能描述:Circular |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。