diff options
Diffstat (limited to 'src/devices/cpu/rw5000/a5900.cpp')
-rw-r--r-- | src/devices/cpu/rw5000/a5900.cpp | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/devices/cpu/rw5000/a5900.cpp b/src/devices/cpu/rw5000/a5900.cpp new file mode 100644 index 00000000000..e294469f35b --- /dev/null +++ b/src/devices/cpu/rw5000/a5900.cpp @@ -0,0 +1,42 @@ +// license:BSD-3-Clause +// copyright-holders:hap +/* + + Rockwell A5900 MCU + +TODO: +- what happens when 0 or >1 keys are held down on READ? + +*/ + +#include "emu.h" +#include "a5900.h" + + +DEFINE_DEVICE_TYPE(A5900, a5900_cpu_device, "a5900", "Rockwell A5900") + + +// constructor +a5900_cpu_device::a5900_cpu_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : + a5000_cpu_device(mconfig, A5900, tag, owner, clock, 9, address_map_constructor(FUNC(a5900_cpu_device::program_512x8), this), 6, address_map_constructor(FUNC(a5900_cpu_device::data_45x4), this)) +{ } + + +// internal memory maps +void a5900_cpu_device::program_512x8(address_map &map) +{ + map(0x000, 0x1ff).rom(); +} + + +//------------------------------------------------- +// changed opcodes (no need for separate file) +//------------------------------------------------- + +void a5900_cpu_device::op_read() +{ + // READ: add _KB (prioritized) to A, skip next on no overflow + m_a += ~((count_leading_zeros_32(m_read_kb() & 0xf) - 28) & 3) & 0xf; + m_skip = !BIT(m_a, 4); + m_a &= 0xf; +} |