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Merge pull request #8007 from enikland2/sms_sscope_read_ram

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sms: SegaScope is write-only, but writes are mirrored in RAM, so read…
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ajrhacker 2021-04-26 21:36:07 -04:00 committed by GitHub
commit 50b4e2e456
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1 changed files with 4 additions and 11 deletions
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src/mame/machine/sms.cpp
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@ -559,17 +559,7 @@ uint8_t gamegear_state::gg_input_port_00_r()
uint8_t sms1_state::sscope_r(offs_t offset)
{
int sscope = m_port_scope->read();
// On SMSJ, address $fffb also controls the built-in 3-D port, that works
// in parallel with the 3-D adapter that is inserted into the card slot.
if ( sscope )
{
// Scope is attached
return m_sscope_state;
}
// SegaScope is write-only and writes are mirrored in RAM, from where the values read come from.
return read_ram(0x3ff8 + offset);
}
@ -578,6 +568,9 @@ void sms1_state::sscope_w(offs_t offset, uint8_t data)
{
write_ram(0x3ff8 + offset, data);
// On SMSJ, address $fffb also controls the built-in 3-D port, that can work
// in parallel with the 3-D adapter that is inserted into the card slot.
int sscope = m_port_scope->read();
if ( sscope )