Samsung S3C8275X User Manual
INSTRUCTION SET
S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X
6-12
CONDITION CODES
The opcode of a conditional jump always contains a 4-bit field called the condition code (cc). This specifies under
which conditions it is to execute the jump. For example, a conditional jump with the condition code for "equal"
after a compare operation only jumps if the two operands are equal. Condition codes are listed in Table 6-6.
which conditions it is to execute the jump. For example, a conditional jump with the condition code for "equal"
after a compare operation only jumps if the two operands are equal. Condition codes are listed in Table 6-6.
The carry (C), zero (Z), sign (S), and overflow (V) flags are used to control the operation of conditional jump
instructions.
instructions.
Table 6-6. Condition Codes
Binary Mnemonic
Description
Flags
Set
0000 F
Always
false
−
1000 T
Always
true
−
0111
(note)
C
Carry
C = 1
1111
(note)
NC
No carry
C = 0
0110
(note)
Z
Zero
Z = 1
1110
(note)
NZ
Not zero
Z = 0
1101
PL
Plus
S = 0
0101
MI
Minus
S = 1
0100
OV
Overflow
V = 1
1100
NOV
No overflow
V = 0
0110
(note)
EQ
Equal
Z = 1
1110
(note)
NE
Not equal
Z = 0
1001
GE
Greater than or equal
(S XOR V) = 0
0001
LT
Less than
(S XOR V) = 1
1010
GT
Greater than
(Z OR (S XOR V)) = 0
0010
LE
Less than or equal
(Z OR (S XOR V)) = 1
1111
(note)
UGE
Unsigned greater than or equal
C = 0
0111
(note)
ULT
Unsigned less than
C = 1
1011
UGT
Unsigned greater than
(C = 0 AND Z = 0) = 1
0011
ULE
Unsigned less than or equal
(C OR Z) = 1
NOTES:
1. It indicates condition codes that are related to two different mnemonics but which test the same flag. For
1. It indicates condition codes that are related to two different mnemonics but which test the same flag. For
example, Z and EQ are both true if the zero flag (Z) is set, but after an ADD instruction, Z would probably be used;
after a CP instruction, however, EQ would probably be used.
2. For operations involving unsigned numbers, the special condition codes UGE, ULT, UGT, and ULE must be used.