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mips3: trivial changes (nw)

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* use the new 64x64 multiply helpers
* make sure unordered exceptions are generated by abs.fmt
* correct an unimportant drc flag
This commit is contained in:
Patrick Mackinlay 2019-02-18 17:09:01 +07:00
parent 12c7311121
commit 4ada281e4c
3 changed files with 13 additions and 80 deletions
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38
src/devices/cpu/mips/mips3.cpp
View File

@ -3530,47 +3530,13 @@ void mips3_device::handle_special(uint32_t op)
m_core->icount -= 35;
break;
case 0x1c: /* DMULT */
{
uint64_t a_hi = (uint32_t)(RSVAL64 >> 32);
uint64_t b_hi = (uint32_t)(RTVAL64 >> 32);
uint64_t a_lo = (uint32_t)RSVAL64;
uint64_t b_lo = (uint32_t)RTVAL64;
uint64_t p1 = a_lo * b_lo;
uint64_t p2 = a_hi * b_lo;
uint64_t p3 = a_lo * b_hi;
uint64_t p4 = a_hi * b_hi;
uint64_t carry = (uint32_t)(((p1 >> 32) + (uint32_t)p2 + (uint32_t)p3) >> 32);
LOVAL64 = p1 + (p2 << 32) + (p3 << 32);
HIVAL64 = p4 + (p2 >> 32) + (p3 >> 32) + carry;
// Adjust for sign
if (RSVAL64 < 0)
HIVAL64 -= RTVAL64;
if (RTVAL64 < 0)
HIVAL64 -= RSVAL64;
LOVAL64 = mul_64x64(RSVAL64, RTVAL64, reinterpret_cast<s64 *>(&HIVAL64));
m_core->icount -= 7;
break;
}
case 0x1d: /* DMULTU */
{
uint64_t a_hi = (uint32_t)(RSVAL64 >> 32);
uint64_t b_hi = (uint32_t)(RTVAL64 >> 32);
uint64_t a_lo = (uint32_t)RSVAL64;
uint64_t b_lo = (uint32_t)RTVAL64;
uint64_t p1 = a_lo * b_lo;
uint64_t p2 = a_hi * b_lo;
uint64_t p3 = a_lo * b_hi;
uint64_t p4 = a_hi * b_hi;
uint64_t carry = (uint32_t)(((p1 >> 32) + (uint32_t)p2 + (uint32_t)p3) >> 32);
LOVAL64 = p1 + (p2 << 32) + (p3 << 32);
HIVAL64 = p4 + (p2 >> 32) + (p3 >> 32) + carry;
LOVAL64 = mulu_64x64(RSVAL64, RTVAL64, &HIVAL64);
m_core->icount -= 7;
break;
}
case 0x1e: /* DDIV */
if (RTVAL64)
{

4
src/devices/cpu/mips/mips3fe.cpp
View File

@ -316,13 +316,13 @@ bool mips3_frontend::describe_special(uint32_t op, opcode_desc &desc)
return true;
case 0x10: // MFHI
desc.regin[0] |= REGFLAG_HI;
desc.regin[2] |= REGFLAG_HI;
desc.regout[0] |= REGFLAG_R(RDREG);
return true;
case 0x11: // MTHI
desc.regin[0] |= REGFLAG_R(RSREG);
desc.regout[0] |= REGFLAG_HI;
desc.regout[2] |= REGFLAG_HI;
return true;
case 0x12: // MFLO

51
src/devices/cpu/mips/r4000.cpp
View File

@ -486,48 +486,12 @@ void r4000_base_device::cpu_execute(u32 const op)
m_icount -= 35;
break;
case 0x1c: // DMULT
{
u64 const a_hi = u32(m_r[RSREG] >> 32);
u64 const b_hi = u32(m_r[RTREG] >> 32);
u64 const a_lo = u32(m_r[RSREG]);
u64 const b_lo = u32(m_r[RTREG]);
u64 const p1 = a_lo * b_lo;
u64 const p2 = a_hi * b_lo;
u64 const p3 = a_lo * b_hi;
u64 const p4 = a_hi * b_hi;
u64 const carry = u32(((p1 >> 32) + u32(p2) + u32(p3)) >> 32);
m_lo = p1 + (p2 << 32) + (p3 << 32);
m_hi = p4 + (p2 >> 32) + (p3 >> 32) + carry;
// adjust for sign
if (s64(m_r[RSREG]) < 0)
m_hi -= m_r[RTREG];
if (s64(m_r[RTREG]) < 0)
m_hi -= m_r[RSREG];
m_icount -= 7;
}
m_lo = mul_64x64(m_r[RSREG], m_r[RTREG], reinterpret_cast<s64 *>(&m_hi));
m_icount -= 7;
break;
case 0x1d: // DMULTU
{
u64 const a_hi = u32(m_r[RSREG] >> 32);
u64 const b_hi = u32(m_r[RTREG] >> 32);
u64 const a_lo = u32(m_r[RSREG]);
u64 const b_lo = u32(m_r[RTREG]);
u64 const p1 = a_lo * b_lo;
u64 const p2 = a_hi * b_lo;
u64 const p3 = a_lo * b_hi;
u64 const p4 = a_hi * b_hi;
u64 const carry = u32(((p1 >> 32) + u32(p2) + u32(p3)) >> 32);
m_lo = p1 + (p2 << 32) + (p3 << 32);
m_hi = p4 + (p2 >> 32) + (p3 >> 32) + carry;
m_icount -= 7;
}
m_lo = mulu_64x64(m_r[RSREG], m_r[RTREG], &m_hi);
m_icount -= 7;
break;
case 0x1e: // DDIV
if (m_r[RTREG])
@ -1797,7 +1761,7 @@ void r4000_base_device::cp1_execute(u32 const op)
if (f32_lt(float32_t{ u32(m_f[FSREG]) }, float32_t{ 0 }))
cp1_set(FDREG, f32_mul(float32_t{ u32(m_f[FSREG]) }, i32_to_f32(-1)).v);
else
m_f[FDREG] = m_f[FSREG];
cp1_set(FDREG, m_f[FSREG]);
}
break;
case 0x06: // MOV.S
@ -2085,7 +2049,7 @@ void r4000_base_device::cp1_execute(u32 const op)
if (f64_lt(float64_t{ m_f[FSREG] }, float64_t{ 0 }))
cp1_set(FDREG, f64_mul(float64_t{ m_f[FSREG] }, i32_to_f64(-1)).v);
else
m_f[FDREG] = m_f[FSREG];
cp1_set(FDREG, m_f[FSREG]);
}
break;
case 0x06: // MOV.D
@ -2808,6 +2772,9 @@ void r4000_base_device::address_error(int intention, u64 const address)
m_cp0[CP0_BadVAddr] = address;
cpu_exception((intention & TRANSLATE_WRITE) ? EXCEPTION_ADES : EXCEPTION_ADEL);
// address errors shouldn't typically occur, so a breakpoint is handy
machine().debug_break();
}
}