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author | Robert <Robbbert@users.noreply.github.com> | 2018-06-07 23:19:11 +1000 |
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committer | GitHub <noreply@github.com> | 2018-06-07 23:19:11 +1000 |
commit | 9b5db920ff3053f53a9710d82aa6c3ef332ef070 (patch) | |
tree | ba87f1c19510fcbf6d3b5bee85cf112420afe12f | |
parent | 7e92c376e8ea0fddf56e6833c49ee8cf37418280 (diff) | |
parent | b62907a03ce6e8f8e7bb26c742e7a63b5613562a (diff) |
Merge pull request #3641 from pmackinlay/interpro
mc146818: don't restart timer unnecessarily (nw)
-rw-r--r-- | src/devices/machine/mc146818.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/devices/machine/mc146818.cpp b/src/devices/machine/mc146818.cpp index 8780643c2e3..254fa8a23b2 100644 --- a/src/devices/machine/mc146818.cpp +++ b/src/devices/machine/mc146818.cpp @@ -582,8 +582,11 @@ WRITE8_MEMBER( mc146818_device::write ) case REG_A: // top bit of A is read only - m_data[REG_A] = data & ~REG_A_UIP; - update_timer(); + if ((data ^ m_data[REG_A]) & ~REG_A_UIP) + { + m_data[REG_A] = data & ~REG_A_UIP; + update_timer(); + } break; case REG_B: |