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e132xs: Cleanups

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- Use count_leading_zeros_32 instead of loop for TESTLZ
- Simplify overflow mask calculation for SHL(I)
This commit is contained in:
AJR 2022-09-20 22:33:45 -04:00
parent 00418d9406
commit 87d91cba68
1 changed files with 3 additions and 10 deletions
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13
src/devices/cpu/e132xs/e132xsop.hxx
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@ -1466,7 +1466,7 @@ void hyperstone_device::hyperstone_shl()
uint32_t n = m_core->local_regs[src_code & 0x3f] & 0x1f;
uint32_t base = m_core->local_regs[dst_code & 0x3f]; /* registers offset by frame pointer */
uint64_t mask = ((((uint64_t)1) << (32 - n)) - 1) ^ 0xffffffff;
uint32_t mask = n ? 0xffffffff << (32 - n) : 0;
SR &= ~(C_MASK | V_MASK | Z_MASK | N_MASK);
@ -1491,14 +1491,7 @@ void hyperstone_device::hyperstone_testlz()
const uint32_t fp = GET_FP;
const uint32_t sreg = m_core->local_regs[(SRC_CODE + fp) & 0x3f];
uint32_t zeros = 0;
for (uint32_t mask = 0x80000000; mask != 0; mask >>= 1 )
{
if (sreg & mask)
break;
else
zeros++;
}
const uint32_t zeros = count_leading_zeros_32(sreg);
m_core->local_regs[(DST_CODE + fp) & 0x3f] = zeros;
@ -2076,7 +2069,7 @@ void hyperstone_device::hyperstone_shli()
SR |= (val & (0x80000000 >> (n - 1))) ? 1 : 0;
}
uint64_t mask = ((1U << (32 - n)) - 1) ^ 0xffffffff;
uint32_t mask = n ? 0xffffffff << (32 - n) : 0;
uint32_t val2 = val << n;
if (((val & mask) && (!(val2 & 0x80000000))) || (((val & mask) ^ mask) && (val2 & 0x80000000)))