The first function is perform_dma, which, not surprisingly, performs DMA commands.
第一个函数是 perform_dma，毫无疑问，该函数执行DMA命令。
This code relies on some utility functions for handling DMA commands. Enter those functions as dma_utils.s
这段代码依赖于一些实用函数来处理DMA命令。
The spu_mfcdma32() function allows DMA from a 32-bit subset of the PPE's theoretical 64-bit address space which is plenty for our purposes.
spu_mfcdma32()函数允许从PPE的（理论上）64位地址空间中的32 位子集中使用DMA 方式获取数据，这对于我们的目的来说已经足够了。
A break above the 21-dma (weekly support) will turn the short-term bias positive.
如突破21日移动均线(本周支撑位)，短期偏见或将转向积极。
Queue DMA GETs for all buffers.
对所有缓冲区的DMA GET进行排队。
Each buffer gets a unique DMA tag ID.
每个缓冲区获得一个惟一的DMA标记ID。
Once the DMA is completed, your function is done.
一旦DMA完成，函数也即完成。
Queue a DMA PUT to transfer the buffer back to main memory.
对DMA PUT 进行排队，从而将缓冲区传输回主内存。
The SPU queues a DMA PUT to transmit the buffer back to main memory.
SPU对DMA PUT进行排队，从而将缓冲区传输回主内存。
Others have DMA engines which need to know the real address on the bus.
另外一些带有dma引擎的设备需要知道总线上的真实地址。
The "tag" is a number which can be assigned to one or many DMA commands.
“标签”是一个数值，可分配给一个或多个dma命令。
DMA transfers are managed by a third peripheral called a DMA controller.
DMA传输由叫DMA控制器的第三方外设进行管理。
The DMA command can also have certain levels of synchronization applied to it.
dma命令也可以应用一些特定级别的同步。
Therefore, they cannot be accessed directly, but must be moved in through DMA.
因而，它们不能被直接访问，而必须通过DMA 移进来。
This command causes the SPE to immediately return with the status of the DMA channels.
这个命令会导致SPE立即返回dma通道的状态。
You then use a DMA command to fetch the full structure, and wait for the DMA to complete.
然后使用dma命令来获取整个结构，等待DMA完成。
Using spu_mfcstat allows you to both check on the status of DMA requests and wait for them.
使用spu_mfcstat让您可以既检查dma请求的状态，又进行等待。
The real power of mailboxes comes when a program combines the mailbox and the DMA approach.
当程序组合使用了邮箱和DMA方法时，才会显出邮箱的真正实力。
Before getting into the details of the main program, I'll explore the DMA utility functions.
在深入介绍主程序细节之前，我要先来探讨一下dma实用函数。
Queue a DMA GETB to refill the buffer with more data after the existing data is stored back.
对DMAGETB进行排队，从而在将现有数据存储回去之后，用更多数据重新填充缓冲区。
The DMA 5000 measures a sample in 40 seconds, considerably increasing efficiency in your lab.
DMA 5000在40秒内测量一种样品，在相当程度上提高实验室的工作效率。
Think of this as a specialized version of the C library function select, but for DMA transfers.
可以把它看作C库函数select的特殊版本，但是针对的是DMA传输。
The SPU queues a DMA GET to pull a portion of the problem data set from main memory to a buffer.
SPU对DMA GET进行排队，从而将涉及的数据集的一部分从主内存传输到一个缓冲区。
The essential hardwares of computer contain CPU, memory, interrupt controller, DMA controller, etc.
计算机硬件的核心器件有CPU、内存、中断控制器、DMA控制器，等等。
The transferTo() method causes the file contents to be copied into a read buffer by the DMA engine.
transferTo()方法引发DMA引擎将文件内容拷贝到一个读取缓冲区。
GETB, PUTB, GETF, and PUTF are the primary fence and barrier-related DMA commands for single buffers.
对于单一缓冲区，GETB、PUTB、GETF和PUTF是与fence和barrier相关的主要dma命令。
The transferTo() method causes the file contents to be copied into a kernel buffer by the DMA engine.
transferTo()方法引发DMA引擎将文件内容拷贝到内核缓冲区。
This is because you are using barriers with your transfers, and you are using the same DMA tag for them.
这是因为正在对传输使用barrier，并对它们使用相同的DMA标签。
This Chapter describes the features common to all the DMAchannels, as well as how DMA operations are set up.
这一章描述了所有DMA通道的公共特征以及如何设置DMA操作。
For instance, one of the problems with the original code is that it is limited to the size of a DMA transfer.
举例来说，原来代码的一个问题是一次dma传输的大小有限制。
应用推荐