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SM8521: don't use rand()

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issue #1004
This commit is contained in:
tildearrow 2023-03-01 15:15:17 -05:00
parent 9a439c248a
commit 814907c0a7
2 changed files with 9 additions and 2 deletions
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8
src/engine/platform/sound/sm8521.c
View file

@ -5,6 +5,9 @@
SM8521 sound emulator SM8521 sound emulator
by cam900 by cam900
MODIFIED BY TILDEARROW
THIS IS NOT THE ORIGINAL VERSION
This file is licensed under zlib license. This file is licensed under zlib license.
============================================================================ ============================================================================
@ -69,7 +72,8 @@ void sm8521_noise_tick(struct sm8521_noise_t *noise, const int cycle)
noise->base.counter += cycle; noise->base.counter += cycle;
while (noise->base.counter >= (noise->base.t + 1)) while (noise->base.counter >= (noise->base.t + 1))
{ {
noise->lfsr = rand() & 0x1; // unknown algorithm // unknown algorithm, but don't use rand()
noise->lfsr = ( noise->lfsr>>1|(((noise->lfsr) ^ (noise->lfsr >> 5) ^ (noise->lfsr >> 8) ^ (noise->lfsr >> 13) ) & 1)<<31);
noise->base.counter -= (noise->base.t + 1); noise->base.counter -= (noise->base.t + 1);
} }
noise->base.out = (((noise->lfsr & 0x1) ? 7 : -8) * noise->base.level) >> 1; // scale out to 8bit noise->base.out = (((noise->lfsr & 0x1) ? 7 : -8) * noise->base.level) >> 1; // scale out to 8bit
@ -125,7 +129,7 @@ void sm8521_reset(struct sm8521_t *sm8521)
sm8521->noise.base.level = 0; sm8521->noise.base.level = 0;
sm8521->noise.base.out = 0; sm8521->noise.base.out = 0;
sm8521->noise.base.counter = 0; sm8521->noise.base.counter = 0;
sm8521->noise.lfsr = 0; sm8521->noise.lfsr = 0x89abcdef;
sm8521->out = 0; sm8521->out = 0;
sm8521->sgda = 0; sm8521->sgda = 0;
sm8521->sgc = 0; sm8521->sgc = 0;

3
src/engine/platform/sound/sm8521.h
View file

@ -5,6 +5,9 @@
SM8521 sound emulator SM8521 sound emulator
by cam900 by cam900
MODIFIED BY TILDEARROW
THIS IS NOT THE ORIGINAL VERSION
This file is licensed under zlib license. This file is licensed under zlib license.
============================================================================ ============================================================================