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romp: various improvements

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* implement multiply/divide step instructions
* privileged instruction exceptions
* corrected borrow flag logic
This commit is contained in:
Patrick Mackinlay 2020-11-30 21:00:18 +07:00
parent cda4ab6526
commit 749acfe07f
1 changed files with 112 additions and 33 deletions
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145
src/devices/cpu/romp/romp.cpp
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@ -9,8 +9,7 @@
* *
* TODO: * TODO:
* - mmu/iocc exceptions * - mmu/iocc exceptions
* - unimplemented instructions (multiply, divide, wait) * - unimplemented instructions (wait)
* - timer/counter
*/ */
#include "emu.h" #include "emu.h"
@ -327,19 +326,27 @@ void romp_device::execute_run()
break; break;
case 0xd0: // lps: load program status case 0xd0: // lps: load program status
if (m_branch_state != BRANCH) if (!(m_scr[ICS] & ICS_US))
{ {
m_branch_target = m_mem.read_dword(r3 + s16(i) + 0); if (m_branch_state != BRANCH)
m_branch_state = BRANCH; {
m_scr[ICS] = m_mem.read_word(r3 + s16(i) + 4); m_branch_target = m_mem.read_dword(r3 + s16(i) + 0);
m_scr[CS] = m_mem.read_word(r3 + s16(i) + 6); m_branch_state = BRANCH;
m_scr[MPCS] &= ~0xffff; m_scr[ICS] = m_mem.read_word(r3 + s16(i) + 4);
// TODO: defer interrupt enable m_scr[CS] = m_mem.read_word(r3 + s16(i) + 6);
if (m_scr[MPCS] & MCS_ALL)
m_scr[MPCS] &= ~MCS_ALL;
else
m_scr[MPCS] &= ~PCS_ALL;
// TODO: defer interrupt enable
m_icount -= 15; m_icount -= 15;
}
else
program_check(PCS_PCK | PCS_IOC);
} }
else else
program_check(PCS_PCK | PCS_IOC); program_check(PCS_PCK | PCS_PIE);
break; break;
case 0xd1: // aei: add extended immediate case 0xd1: // aei: add extended immediate
flags_add(m_gpr[R3], s32(s16(i)) + bool(m_scr[CS] & CS_C)); flags_add(m_gpr[R3], s32(s16(i)) + bool(m_scr[CS] & CS_C));
@ -456,10 +463,15 @@ void romp_device::execute_run()
m_icount -= 3; m_icount -= 3;
break; break;
case 0x96: // mfs: move from scr case 0x96: // mfs: move from scr
if (R2 == IAR) if (!(m_scr[ICS] & ICS_US) || R2 == MQ || R2 == CS)
m_gpr[R3] = updated_iar; {
if (R2 == IAR)
m_gpr[R3] = updated_iar;
else
m_gpr[R3] = m_scr[R2];
}
else else
m_gpr[R3] = m_scr[R2]; program_check(PCS_PCK | PCS_PIE);
m_icount--; m_icount--;
break; break;
case 0x97: // setsb: set scr bit case 0x97: // setsb: set scr bit
@ -588,8 +600,30 @@ void romp_device::execute_run()
m_icount -= 2; m_icount -= 2;
break; break;
case 0xb6: // d: divide step case 0xb6: // d: divide step
// m_icount -= 2; {
fatalerror("divide step (%s)\n", machine().describe_context()); s64 sum = (s64(s32(m_gpr[R2])) << 1) | (m_scr[MQ] >> 31);
if (BIT(m_gpr[R2], 31) == BIT(m_gpr[R3], 31))
sum -= s32(m_gpr[R3]);
else
sum += s32(m_gpr[R3]);
// update remainder
m_gpr[R2] = sum;
// update quotient
m_scr[MQ] <<= 1;
if (BIT(sum, 32) == BIT(m_gpr[R3], 31))
{
m_scr[MQ] |= 1;
m_scr[CS] |= CS_C;
}
// overflow test
if (BIT(sum, 32) == BIT(m_gpr[R2], 31))
m_scr[CS] |= CS_O;
}
m_icount -= 2;
break; break;
case 0xb8: // sr: shift right case 0xb8: // sr: shift right
m_gpr[R2] >>= (m_gpr[R3] & 63); m_gpr[R2] >>= (m_gpr[R3] & 63);
@ -670,8 +704,40 @@ void romp_device::execute_run()
flags_log(m_gpr[R2]); flags_log(m_gpr[R2]);
break; break;
case 0xe6: // m: multiply step case 0xe6: // m: multiply step
// m_icount -= 3; {
fatalerror("multiply step (%s)\n", machine().describe_context()); s64 sum = s32(m_gpr[R2]);
if (m_scr[CS] & CS_C)
{
// no carry
switch (m_scr[MQ] & 3)
{
case 1: sum += s32(m_gpr[R3]); break;
case 2: sum -= s64(s32(m_gpr[R3])) * 2; break;
case 3: sum -= s32(m_gpr[R3]); break;
}
}
else
{
// carry
switch (m_scr[MQ] & 3)
{
case 0: sum += s32(m_gpr[R3]); break;
case 1: sum += s64(s32(m_gpr[R3])) * 2; break;
case 2: sum -= s32(m_gpr[R3]); break;
}
}
// update carry flag
if (m_scr[MQ] & 2)
m_scr[CS] &= ~CS_C;
else
m_scr[CS] |= CS_C;
m_scr[MQ] = (sum << 30) | (m_scr[MQ] >> 2);
m_gpr[R2] = sum >> 2;
}
m_icount -= 3;
break; break;
case 0xe7: // x: exclusive or case 0xe7: // x: exclusive or
m_gpr[R2] ^= m_gpr[R3]; m_gpr[R2] ^= m_gpr[R3];
@ -744,17 +810,23 @@ void romp_device::execute_run()
break; break;
case 0xf0: // wait: wait case 0xf0: // wait: wait
// if (m_branch_state == BRANCH) if (!(m_scr[ICS] & ICS_US))
// program_check(PCS_PCK | PCS_IOC); {
fatalerror("wait (%s)\n", machine().describe_context()); if (m_branch_state != BRANCH)
fatalerror("wait (%s)\n", machine().describe_context());
else
program_check(PCS_PCK | PCS_IOC);
}
else
program_check(PCS_PCK | PCS_PIE);
break; break;
case 0xf1: // ae: add extended case 0xf1: // ae: add extended
flags_add(m_gpr[R2], m_gpr[R3] + bool(m_scr[CS] & CS_C)); flags_add(m_gpr[R2], m_gpr[R3] + bool(m_scr[CS] & CS_C));
m_gpr[R2] += m_gpr[R3] + bool(m_scr[CS] & CS_C); m_gpr[R2] += m_gpr[R3] + bool(m_scr[CS] & CS_C);
break; break;
case 0xf2: // se: subtract extended case 0xf2: // se: subtract extended
flags_sub(m_gpr[R2], m_gpr[R3] + bool(m_scr[CS] & CS_C)); flags_add(m_gpr[R2], ~m_gpr[R3] + bool(m_scr[CS] & CS_C));
m_gpr[R2] -= m_gpr[R3] + bool(m_scr[CS] & CS_C); m_gpr[R2] += ~m_gpr[R3] + bool(m_scr[CS] & CS_C);
break; break;
case 0xf3: // ca16: compute address 16-bit case 0xf3: // ca16: compute address 16-bit
m_gpr[R2] = (m_gpr[R3] & 0xffff'0000U) | (u16(m_gpr[R2]) + u16(m_gpr[R3])); m_gpr[R2] = (m_gpr[R3] & 0xffff'0000U) | (u16(m_gpr[R2]) + u16(m_gpr[R3]));
@ -830,17 +902,22 @@ void romp_device::set_scr(unsigned scr, u32 data)
LOG("set_scr %s data 0x%08x (%s)\n", scr_names[scr], data, machine().describe_context()); LOG("set_scr %s data 0x%08x (%s)\n", scr_names[scr], data, machine().describe_context());
switch (scr) if (!(m_scr[ICS] & ICS_US) || scr == MQ || scr == CS)
{ {
case ICS: switch (scr)
space(bool(data & ICS_TM)).cache(m_mem); {
break; case ICS:
space(bool(data & ICS_TM)).cache(m_mem);
break;
default: default:
break; break;
}
m_scr[scr] = data;
} }
else
m_scr[scr] = data; program_check(PCS_PCK | PCS_PIE);
} }
void romp_device::execute_set_input(int irqline, int state) void romp_device::execute_set_input(int irqline, int state)
@ -925,7 +1002,7 @@ void romp_device::flags_sub(u32 const op1, u32 const op2)
{ {
u32 const result = op1 - op2; u32 const result = op1 - op2;
m_scr[CS] &= ~(CS_L | CS_E | CS_G | CS_C | CS_O); m_scr[CS] &= ~(CS_L | CS_E | CS_G | CS_O);
if (result == 0) if (result == 0)
m_scr[CS] |= CS_E; m_scr[CS] |= CS_E;
@ -935,8 +1012,10 @@ void romp_device::flags_sub(u32 const op1, u32 const op2)
else else
m_scr[CS] |= CS_G; m_scr[CS] |= CS_G;
// carry // borrow
if ((!BIT(op2, 31) && BIT(op1, 31)) || (BIT(result, 31) && (!BIT(op2, 31) || BIT(op1, 31)))) if ((!BIT(op2, 31) && BIT(op1, 31)) || (BIT(result, 31) && (!BIT(op2, 31) || BIT(op1, 31))))
m_scr[CS] &= ~CS_C;
else
m_scr[CS] |= CS_C; m_scr[CS] |= CS_C;
// overflow // overflow