diff options
author | 2020-04-23 01:21:39 +0200 | |
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committer | 2020-04-23 01:22:00 +0200 | |
commit | 68f42bc6debf2fb8c05737ec2698bbdcc514eac7 (patch) | |
tree | 7d16ec456f346b158940c21d024e37a2095ae2a3 /src/devices/cpu/hmcs40/hmcs40op.cpp | |
parent | 859d4943d63df5f6510ff277ae8dda4d849cd146 (diff) |
hmcs40: change stack op (nw)
Diffstat (limited to 'src/devices/cpu/hmcs40/hmcs40op.cpp')
-rw-r--r-- | src/devices/cpu/hmcs40/hmcs40op.cpp | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/src/devices/cpu/hmcs40/hmcs40op.cpp b/src/devices/cpu/hmcs40/hmcs40op.cpp index a10629cf639..a0c6c6efb5c 100644 --- a/src/devices/cpu/hmcs40/hmcs40op.cpp +++ b/src/devices/cpu/hmcs40/hmcs40op.cpp @@ -21,18 +21,26 @@ inline void hmcs40_cpu_device::ram_w(u8 data) m_data->write_byte(address, data & 0xf); } +void hmcs40_cpu_device::exc_stack() +{ + // exchange stack/pc + u16 pc = m_stack[m_sp] & m_pcmask; + m_stack[m_sp] = m_pc; + m_pc = pc; +} + void hmcs40_cpu_device::pop_stack() { - m_pc = m_stack[0] & m_pcmask; - for (int i = 0; i < m_stack_levels-1; i++) - m_stack[i] = m_stack[i+1]; + if (++m_sp >= m_stack_levels) + m_sp = 0; + exc_stack(); } void hmcs40_cpu_device::push_stack() { - for (int i = m_stack_levels-1; i >= 1; i--) - m_stack[i] = m_stack[i-1]; - m_stack[0] = m_pc; + exc_stack(); + if (--m_sp < 0) + m_sp = m_stack_levels - 1; } |