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i960: Shift opcode fixes

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- Ensure logically correct results for shift counts >= 32
- Preserve sign for shli
This commit is contained in:
AJR 2023-04-22 10:18:25 -04:00
parent 35cb398d8a
commit 4cce14ef15
1 changed files with 10 additions and 5 deletions
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15
src/devices/cpu/i960/i960.cpp
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@ -1110,14 +1110,16 @@ void i960_cpu_device::execute_op(uint32_t opcode)
m_icount--;
t1 = get_1_ri(opcode);
t2 = get_2_ri(opcode);
set_ri(opcode, t2>>t1);
set_ri(opcode, t1 >= 32 ? 0 : t2>>t1);
break;
case 0xa: // shrdi
m_icount--;
t1 = get_1_ri(opcode);
t2 = get_2_ri(opcode);
if(((int32_t)t2) < 0) {
if(t1 >= 32)
set_ri(opcode, 0);
else if(((int32_t)t2) < 0) {
if(t2 & ((1<<t1)-1))
set_ri(opcode, (((int32_t)t2)>>t1)+1);
else
@ -1130,14 +1132,17 @@ void i960_cpu_device::execute_op(uint32_t opcode)
m_icount--;
t1 = get_1_ri(opcode);
t2 = get_2_ri(opcode);
set_ri(opcode, ((int32_t)t2)>>t1);
if(t1 >= 32)
set_ri(opcode, (int32_t)t2 < 0 ? -1 : 0);
else
set_ri(opcode, ((int32_t)t2)>>t1);
break;
case 0xc: // shlo
m_icount--;
t1 = get_1_ri(opcode);
t2 = get_2_ri(opcode);
set_ri(opcode, t2<<t1);
set_ri(opcode, t1 >= 32 ? 0 : t2<<t1);
break;
case 0xd: // rotate
@ -1152,7 +1157,7 @@ void i960_cpu_device::execute_op(uint32_t opcode)
m_icount--;
t1 = get_1_ri(opcode);
t2 = get_2_ri(opcode);
set_ri(opcode, t2<<t1);
set_ri(opcode, (t2 & 0x80000000) | (t1 >= 32 ? 0 : (t2<<t1) & 0x7fffffff)); // sign is preserved
break;
default: