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| author | YamaArashi <shadow962@live.com> | 2016-10-02 14:24:34 -0700 |
|---|---|---|
| committer | YamaArashi <shadow962@live.com> | 2016-10-02 14:24:34 -0700 |
| commit | f522ceb65e5206134e64e36e52eb866adcc9f543 (patch) | |
| tree | 21ef4eed3181d38f1f0bbc9ac6db1de1c25cf17c | |
| parent | 43f374e64e6c0ee10bc38af9c064a3411ba88c85 (diff) | |
add comment for DMA clear macros
| -rw-r--r-- | include/gba/macro.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/gba/macro.h b/include/gba/macro.h index c8139eb97..62d3e73fa 100644 --- a/include/gba/macro.h +++ b/include/gba/macro.h @@ -49,6 +49,11 @@ #define DmaFill16(dmaNum, value, dest, size) DMA_FILL(dmaNum, value, dest, size, 16) #define DmaFill32(dmaNum, value, dest, size) DMA_FILL(dmaNum, value, dest, size, 32) +// Note that the DMA clear macros cause the DMA control value to be calculated +// at runtime rather than compile time. The size is divided by the DMA transfer +// unit size (2 or 4 bytes) and then combined with the DMA control flags using a +// bitwise OR operation. + #define DMA_CLEAR(dmaNum, dest, size, bit) \ { \ vu##bit *_dest = (vu##bit *)(dest); \ |