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authorMichael Sevakis <jethead71@rockbox.org>2010-06-30 07:08:10 +0000
committerMichael Sevakis <jethead71@rockbox.org>2010-06-30 07:08:10 +0000
commit90a26718330f58a884d3ddb603e3e1c3cb333958 (patch)
treec51945ced8a57f3a6f121f2fefe32fd3f15a46bc /firmware
parentd2ed594246d2840ee09445483a03bb4b5baaff4b (diff)
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i.MX31: Make DMA ISR call loop a bit more efficient.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27192 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware')
-rw-r--r--firmware/target/arm/imx31/sdma-imx31.c16
1 files changed, 5 insertions, 11 deletions
diff --git a/firmware/target/arm/imx31/sdma-imx31.c b/firmware/target/arm/imx31/sdma-imx31.c
index 39f4e29554..68aa0aa35f 100644
--- a/firmware/target/arm/imx31/sdma-imx31.c
+++ b/firmware/target/arm/imx31/sdma-imx31.c
@@ -53,19 +53,13 @@ static void __attribute__((interrupt("IRQ"))) SDMA_HANDLER(void)
SDMA_INTR = pending; /* Ack all ints */
pending &= sdma_enabled_ints; /* Only dispatch ints with callback */
- while (1)
+ while (pending)
{
- unsigned int channel;
+ unsigned int bit = pending & -pending; /* Isolate bottom bit */
+ pending &= ~bit; /* Clear it */
- if (pending == 0)
- break; /* No bits set */
-
- channel = find_first_set_bit(pending);
-
- pending &= ~(1ul << channel);
-
- /* Call callback (required if using an interrupt) */
- ccb_array[channel].channel_desc->callback();
+ /* Call callback (required if using an interrupt). bit number = channel */
+ ccb_array[31 - __builtin_clz(bit)].channel_desc->callback();
}
}