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mcs48: A better fix for the JNI problem (nw)

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This commit is contained in:
AJR 2019-07-02 22:55:12 -04:00
parent 5afea7f637
commit 0ca3401a04
2 changed files with 11 additions and 7 deletions
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16
src/devices/cpu/mcs48/mcs48.cpp
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@ -750,8 +750,8 @@ OPHANDLER( jc ) { execute_jcc((m_psw & C_FLAG) != 0); return 2; }
OPHANDLER( jf0 ) { execute_jcc((m_psw & F_FLAG) != 0); return 2; }
OPHANDLER( jf1 ) { execute_jcc((m_sts & STS_F1) != 0); return 2; }
OPHANDLER( jnc ) { execute_jcc((m_psw & C_FLAG) == 0); return 2; }
OPHANDLER( jni ) { execute_jcc(m_irq_state != 0); return 2; }
OPHANDLER( jnibf ) { execute_jcc((m_sts & STS_IBF) == 0); return 2; }
OPHANDLER( jni ) { m_irq_polled = (m_irq_state == 0); execute_jcc(m_irq_state != 0); return 2; }
OPHANDLER( jnibf ) { m_irq_polled = (m_sts & STS_IBF) != 0; execute_jcc((m_sts & STS_IBF) == 0); return 2; }
OPHANDLER( jnt_0 ) { execute_jcc(test_r(0) == 0); return 2; }
OPHANDLER( jnt_1 ) { execute_jcc(test_r(1) == 0); return 2; }
OPHANDLER( jnz ) { execute_jcc(m_a != 0); return 2; }
@ -1103,7 +1103,7 @@ void mcs48_cpu_device::device_start()
m_dbbi = 0;
m_dbbo = 0;
m_irq_state = 0;
m_pending_irq_state = 0;
m_irq_polled = 0;
/* FIXME: Current implementation suboptimal */
m_ea = (m_int_rom_size ? 0 : 1);
@ -1175,6 +1175,7 @@ void mcs48_cpu_device::device_start()
save_item(NAME(m_dbbo));
save_item(NAME(m_irq_state));
save_item(NAME(m_irq_polled));
save_item(NAME(m_irq_in_progress));
save_item(NAME(m_timer_overflow));
save_item(NAME(m_timer_flag));
@ -1228,17 +1229,19 @@ void mcs48_cpu_device::device_reset()
int mcs48_cpu_device::check_irqs()
{
bool pending_irq = std::exchange(m_pending_irq_state, m_irq_state);
/* if something is in progress, we do nothing */
if (m_irq_in_progress)
return 0;
/* external interrupts take priority */
if ((pending_irq || (m_sts & STS_IBF) != 0) && m_xirq_enabled)
if ((m_irq_state || (m_sts & STS_IBF) != 0) && m_xirq_enabled)
{
m_irq_in_progress = true;
// force JNI to be taken (hack)
if (m_irq_polled)
m_pc = ((m_pc - 1) & 0xf00) | m_cache->read_byte(m_pc - 1);
/* transfer to location 0x03 */
push_pc_psw();
m_pc = 0x03;
@ -1332,6 +1335,7 @@ void mcs48_cpu_device::execute_run()
/* fetch next opcode */
m_prevpc = m_pc;
m_irq_polled = false;
debugger_instruction_hook(m_pc);
opcode = opcode_fetch();

2
src/devices/cpu/mcs48/mcs48.h
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@ -208,7 +208,7 @@ protected:
uint8_t m_dbbo; /* 8-bit output data buffer (UPI-41 only) */
bool m_irq_state; /* true if the IRQ line is active */
bool m_pending_irq_state; /* true if an IRQ is pending */
bool m_irq_polled; /* true if last instruction was JNI (and not taken) */
bool m_irq_in_progress; /* true if an IRQ is in progress */
bool m_timer_overflow; /* true on a timer overflow; cleared by taking interrupt */
bool m_timer_flag; /* true on a timer overflow; cleared on JTF */