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CS423x: Replace Mu-Law and A-Law functions with more efficient ones

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This commit is contained in:
RichardG867
2022-03-07 17:11:35 -03:00
parent 9f40c213a6
commit 669a6a2e49
1 changed files with 20 additions and 19 deletions
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39
src/sound/snd_ad1848.c
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@@ -422,32 +422,33 @@ ad1848_update(ad1848_t *ad1848)
static int16_t static int16_t
ad1848_process_mulaw(uint8_t byte) ad1848_process_mulaw(uint8_t byte)
{ {
int pos; byte = ~byte;
int16_t dec; int16_t dec = ((byte & 0x0f) << 3) + 0x84;
dec <<= (byte & 0x70) >> 4;
dec = (~byte) & 0x7f; return (byte & 0x80) ? (0x84 - dec) : (dec - 0x84);
pos = ((dec & 0xf0) >> 4) + 5;
dec = (1 << pos) | ((dec & 0x0f) << (pos - 4)) | (1 << (pos - 5));
dec = (dec - 33) << 2;
return (byte & 0x80) ? dec : -dec;
} }
static int16_t static int16_t
ad1848_process_alaw(uint8_t byte) ad1848_process_alaw(uint8_t byte)
{ {
int pos;
int16_t dec;
byte ^= 0x55; byte ^= 0x55;
uint8_t sample = byte & 0x7f; int16_t dec = (byte & 0x0f) << 4;
pos = ((sample & 0xf0) >> 4) + 4; int seg = (byte & 0x70) >> 4;
if (pos == 4) switch (seg) {
dec = (sample << 4) | 0x08; case 0:
else dec += 0x8;
dec = (1 << (pos + 3)) | ((sample & 0x0f) << (pos - 1)) | (1 << (pos - 2)); break;
return (byte & 0x80) ? -dec : dec; case 1:
dec += 0x108;
break;
default:
dec += 0x108;
dec <<= seg - 1;
break;
}
return (byte & 0x80) ? dec : -dec;
} }
static int16_t static int16_t