SVC: Difference between revisions

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= DMA =

The CTRSDK code for using svcStartInterProcessDma will execute svcBreak when svcStartInterProcessDma returns an error(except for certain error value(s)). Therefore on retail, triggering a svcStartInterProcessDma via a system-module which results in an error from svcStartInterProcessDma will result in the system-module terminating.

==DmaConfig==

Size of struct is 24 bytes.

struct DmaConfig {

sint8_t channel_sel; // @0 Selects which DMA channel to use: 0-7, -1 = don't care.

uint8_t unk1; // @1 Accepted values: 0,2,4,8.

uint8_t flags; // @2 bit0: DST_CFG, bit1: SRC_CFG, bit2: SHALL_BLOCK, bit3: ???, bit6: DST_ALT_CFG, bit7: DST_ALT_CFG

uint8_t dst_cfg[10];

// @5 Accepted values (u8): 4, 8, 12, 15.

// @15 Accepted values (u8): 4, 8, 12, 15.

uint8_t src_cfg[10]; // @14

}

If SRC_CFG/DST_CFG is set in the flags field, the configuration for src/dst is loaded from src_cfg/dst_cfg respectively. If the *_ALT_CFG flag is set same thing goes, except byte0 of each cfg is forced to 0xFF. ALT_CFG has priority over CFG.

If CFG or ALT_CFG is not set, default configuration is loaded:

FF 0F 80 00 00 00 80 00 00 00

If SHALL_BLOCK is set, the thread will sleep until the DMA engine is ready. If not set, the SVC will return 0xD04007F0 if the DMA channel is busy.

The format of src_cfg/dst_cfg is unknown, but both have the same format. Checks suggest that the second byte of cfg equalling 4 means NO_INCREMENT (don't increment after read/write).

= Debugging =

@@ Line 1,075: / Line 1,075: @@
 = DMA =
 The CTRSDK code for using svcStartInterProcessDma will execute svcBreak when svcStartInterProcessDma returns an error(except for certain error value(s)). Therefore on retail, triggering a svcStartInterProcessDma via a system-module which results in an error from svcStartInterProcessDma will result in the system-module terminating.
+==DmaConfig==
+Size of struct is 24 bytes.
+ struct DmaConfig {
+     sint8_t channel_sel; // @0 Selects which DMA channel to use: 0-7, -1 = don't care.
+     uint8_t unk1;        // @1 Accepted values: 0,2,4,8.
+     uint8_t flags;       // @2 bit0: DST_CFG, bit1: SRC_CFG, bit2: SHALL_BLOCK, bit3: ???, bit6: DST_ALT_CFG, bit7: DST_ALT_CFG
+     uint8_t dst_cfg[10];
+     // @5 Accepted values (u8): 4, 8, 12, 15.
+     // @15 Accepted values (u8): 4, 8, 12, 15.
+     uint8_t src_cfg[10]; // @14
+ }
+If SRC_CFG/DST_CFG is set in the flags field, the configuration for src/dst is loaded from src_cfg/dst_cfg respectively. If the *_ALT_CFG flag is set same thing goes, except byte0 of each cfg is forced to 0xFF. ALT_CFG has priority over CFG.
+If CFG or ALT_CFG is not set, default configuration is loaded:
+ FF 0F 80 00 00 00 80 00 00 00
+If SHALL_BLOCK is set, the thread will sleep until the DMA engine is ready. If not set, the SVC will return 0xD04007F0 if the DMA channel is busy.
+The format of src_cfg/dst_cfg is unknown, but both have the same format. Checks suggest that the second byte of cfg equalling 4 means NO_INCREMENT (don't increment after read/write).
 = Debugging =