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[Core/Sound] accurate YM2612/3438 status read emulation on invalid port

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This commit is contained in:
nukeykt 2018-01-29 13:24:13 +09:00
parent fee2bc8c28
commit 06b3950d73
2 changed files with 20 additions and 3 deletions
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21
core/sound/ym3438.c
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@ -1355,6 +1355,9 @@ void OPN2_Clock(ym3438_t *chip, Bit16s *buffer)
buffer[0] = chip->mol;
buffer[1] = chip->mor;
if (chip->status_time)
chip->status_time--;
}
void OPN2_Write(ym3438_t *chip, Bit32u port, Bit8u data)
@ -1411,18 +1414,30 @@ Bit8u OPN2_Read(ym3438_t *chip, Bit32u port)
}
if (chip->mode_test_21[7])
{
return testdata & 0xff;
chip->status = testdata & 0xff;
}
else
{
return testdata >> 8;
chip->status = testdata >> 8;
}
}
else
{
return (chip->busy << 7) | (chip->timer_b_overflow_flag << 1)
chip->status = (chip->busy << 7) | (chip->timer_b_overflow_flag << 1)
| chip->timer_a_overflow_flag;
}
if (chip_type == ym3438_type_ym2612)
{
chip->status_time = 300000;
}
else
{
chip->status_time = 40000000;
}
}
if (chip->status_time)
{
return chip->status;
}
return 0;
}

2
core/sound/ym3438.h
View File

@ -205,6 +205,8 @@ typedef struct
Bit8u pan_l[6], pan_r[6];
Bit8u ams[6];
Bit8u pms[6];
Bit8u status;
Bit32u status_time;
} ym3438_t;
void OPN2_Reset(ym3438_t *chip);