From a124e87f846fb2ab363859e5a8ea4e6dab7b0e31 Mon Sep 17 00:00:00 2001 From: Linus Nielsen Feltzing Date: Wed, 19 Jun 2002 12:44:32 +0000 Subject: Accelerated bit swapping git-svn-id: svn://svn.rockbox.org/rockbox/trunk@1075 a1c6a512-1295-4272-9138-f99709370657 --- firmware/mpeg.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'firmware') diff --git a/firmware/mpeg.c b/firmware/mpeg.c index 18c8e701fd..eda08e139d 100644 --- a/firmware/mpeg.c +++ b/firmware/mpeg.c @@ -119,6 +119,8 @@ static unsigned char fliptable[] = 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff }; +static unsigned short big_fliptable[65536]; + static struct event_queue mpeg_queue; static int mpeg_stack[MPEG_STACK_SIZE/sizeof(int)]; @@ -138,6 +140,16 @@ static bool filling; /* We are filling the buffer with data from disk */ static int mpeg_file; +static void create_fliptable(void) +{ + int i; + + for(i = 0;i < 65536;i++) + { + big_fliptable[i] = fliptable[i & 0xff] | (fliptable[i >> 8] << 8); + } +} + static void mas_poll_start(int interval_in_ms) { unsigned int count; @@ -207,12 +219,12 @@ static void dma_tick(void) } } -static void bitswap(unsigned char *data, int length) +static void bitswap(unsigned short *data, int length) { int i = length; while(i--) { - data[i] = fliptable[data[i]]; + data[i] = big_fliptable[data[i]]; } } @@ -393,7 +405,9 @@ static void mpeg_thread(void) if(len > 0) { DEBUGF("B\n"); - bitswap(mp3buf + mp3buf_write, len); + + bitswap((unsigned short *)(mp3buf + mp3buf_write), + (len+1)/2); mp3buf_write += len; if(mp3buf_write >= mp3buflen) @@ -609,6 +623,8 @@ void mpeg_init(void) mp3buflen = mp3end - mp3buf; + create_fliptable(); + queue_init(&mpeg_queue); create_thread(mpeg_thread, mpeg_stack, sizeof(mpeg_stack)); -- cgit v1.2.3