Computer Hardware Algorithm Standard User's Guide

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A.5 DMA Guidelines
DMA Guidelines
Guideline 12 — All C6x algorithms should be supplied in both little- and big-endian formats. (See
Section 5.3.1 )
Guideline 13 — On processors that support large program model compilations, a version of the algorithm
should be supplied that accesses all core run-time support functions as near functions and all
algorithms as far functions (mixed model). (See Section 5.4.2 )
Guideline 14 — All C55x algorithms should not assume any specific stack configuration and should work
under all the three stack modes. (See Section 5.5.1 )
DMA Guideline 1 — The data transfer should complete before the CPU operations executing in parallel
(DMA guideline). (See Section 6.6 )
DMA Guideline 2 — All algorithms should minimize channel (re)configuration overhead by requesting a
dedicated logical DMA channel for each distinct type of DMA transfer it issues, and avoid calling
ACPY2 configure and preferring the new fast configuration APIs where possible. (See Section 6.12 )
DMA Guideline 3 — To ensure correctness, All C6000 algorithms that implement IDMA2 need to be
supplied with the internal memory they request from the client applciation using algAlloc(). (See
Section 6.13.1 )
DMA Guideline 4 — To facilitate high performance, C55x algorithms should request DMA transfers with
source and destinations aligned on 32-bit byte addresses. (See Section 6.14.1 )
DMA Guideline 5 — C55x algorithms should minimize channel configuration overhead by requesting a
separate logical channel for each different transfer type. They should also call ACPY2_configure
when the source or destination addresses belong in a different type of memory (SARAM, DARAM,
External) as compared with that of the most recent transfer. (See Section 6.14.2 )
SPRU352G – June 2005 – Revised February 2007 Rules and Guidelines 79
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