MI_SendGXCommand


C Specification

#include <nitro/mi.h>

void MI_SendGXCommand( 
          u32       dmaNo, 
    const void*     src, 
          u32       commandLength );

void MI_SendGXCommandAsync( 
          u32       dmaNo, 
    const void*     src, 
          u32       commandLength,
    MIDmaCallback   callback, 
          void*     arg );

Description

This function uses DMA to send a display list (GX command string) to command FIFO. The transfer source address must be 4-byte aligned.

The synchronous version of MI_SendGXCommand() ends DMA inside the function. The asynchronous version of MI_SendGXCommandAsync() uses a callback function when DMA ends. The callback function is an MIDmaCallback type function (a void type function with a void* type argument).

For MI_SendGXCommandAsync(), specifying NULL for callback is the equivalent of calling the synchronous version of MI_SendGXCommand().

The difference between MI_SendGXCommandAsync() and MI_SendGXCommandAsyncFast():

Note that multiple automatic DMAs cannot be used simultaneously because of hardware restrictions. However, the hardware allows the simultaneous startup of multiple automatic DMAs of the same type.

With NITRO-SDK, the exclusion process of MI_SendGXCommandAsync() with other G3_ type API is not performed because of the priority of operation speed of the graphics command. Therefore, we cannot guarantee correct operation if the GX command is written directly to command FIFO by a G3_ function while the GX command is being transferred by MI_SendGXCommandAsync(). It is strongly recommended that you pay particular attention in avoiding such a situation on the API call side.

Internal Operation

Uses the following IO registers: DMAn source register (0x40000B0 + 12n), DMAn destination register (0x40000B4 + 12n), and DMAn control register (0x40000B8 + 12n). (n is the DMA channel used.) The GXFIFO(0x4000400) IO register is also accessed.

Arguments

dmaNo DMA channel used
src Transmit source address
commandLength Transmit command size
callback Callback when DMA ends
arg Callback argument when DMA ends

Return Values

None

See Also

MI_DmaCopy*, G3_BeginMakeDL, G3_EndMakeDL

Revision History

08/26/2004 Added description for MI_SendGXCommandAsyncFast
07/18/2004 Added description when the callback is NULL
12/01/2003 Initial version