Sprinter/mame
2
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge pull request #8007 from enikland2/sms_sscope_read_ram

Browse Source 
sms: SegaScope is write-only, but writes are mirrored in RAM, so read…
This commit is contained in:
ajrhacker 2021-04-26 21:36:07 -04:00 committed by GitHub
commit 50b4e2e456
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 4 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
src/mame/machine/sms.cpp
View File

@ -559,17 +559,7 @@ uint8_t gamegear_state::gg_input_port_00_r()
uint8_t sms1_state::sscope_r(offs_t offset) uint8_t sms1_state::sscope_r(offs_t offset)
{ {
int sscope = m_port_scope->read(); // SegaScope is write-only and writes are mirrored in RAM, from where the values read come from.
// 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;
}
return read_ram(0x3ff8 + offset); 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); 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(); int sscope = m_port_scope->read();
if ( sscope ) if ( sscope )