gem5  v21.1.0.2
condcodes.hh
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28 
29 #ifndef __BASE_CONDCODE_HH__
30 #define __BASE_CONDCODE_HH__
31 
32 #include "base/bitfield.hh"
33 
34 namespace gem5
35 {
36 
83 static inline bool
84 findCarry(int width, uint64_t dest, uint64_t src1, uint64_t src2)
85 {
86  int shift = width - 1;
87  return ((~(dest >> shift) & 1) +
88  ((src1 >> shift) & 1) +
89  ((src2 >> shift) & 1)) & 0x2;
90 }
91 
97 static inline bool
98 findOverflow(int width, uint64_t dest, uint64_t src1, uint64_t src2)
99 {
100  int shift = width - 1;
101  return ((src1 ^ ~src2) & (src1 ^ dest)) & (1ULL << shift);
102 }
103 
122 static inline bool
123 findParity(int width, uint64_t dest)
124 {
125  dest &= mask(width);
126  dest ^= (dest >> 32);
127  dest ^= (dest >> 16);
128  dest ^= (dest >> 8);
129  dest ^= (dest >> 4);
130  dest ^= (dest >> 2);
131  dest ^= (dest >> 1);
132  return dest & 1;
133 }
134 
140 static inline bool
141 findNegative(int width, uint64_t dest)
142 {
143  return bits(dest, width - 1);
144 }
145 
151 static inline bool
152 findZero(int width, uint64_t dest)
153 {
154  return !(dest & mask(width));
155 }
156 
157 } // namespace gem5
158 
159 #endif // __BASE_CONDCODE_HH__
gem5::mask
constexpr uint64_t mask(unsigned nbits)
Generate a 64-bit mask of 'nbits' 1s, right justified.
Definition: bitfield.hh:63
gem5::ArmISA::shift
Bitfield< 6, 5 > shift
Definition: types.hh:117
gem5::findOverflow
static bool findOverflow(int width, uint64_t dest, uint64_t src1, uint64_t src2)
Calculate the overflow flag from an addition.
Definition: condcodes.hh:98
gem5::findZero
static bool findZero(int width, uint64_t dest)
Calculate the zero flag.
Definition: condcodes.hh:152
bitfield.hh
gem5::ArmISA::width
Bitfield< 4 > width
Definition: misc_types.hh:71
gem5::findCarry
static bool findCarry(int width, uint64_t dest, uint64_t src1, uint64_t src2)
Calculate the carry flag from an addition.
Definition: condcodes.hh:84
gem5::bits
constexpr T bits(T val, unsigned first, unsigned last)
Extract the bitfield from position 'first' to 'last' (inclusive) from 'val' and right justify it.
Definition: bitfield.hh:76
gem5::findParity
static bool findParity(int width, uint64_t dest)
Calculate the parity of a value.
Definition: condcodes.hh:123
gem5::findNegative
static bool findNegative(int width, uint64_t dest)
Calculate the negative flag.
Definition: condcodes.hh:141
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: decoder.cc:40

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