Texas Instruments TMS320C28x Reference Manual page 549

XRETC COND
XRETC COND
SYNTAX OPTIONS
XRETC COND
Operands COND
Description
Flags and V
Modes
Repeat
6-392
0101 0110 1111 COND
Conditional codes:
COND Syntax Description
0000 NEQ Not Equal To
0001 EQ Equal To
0010 GT Greater Then
0011 GEQ Greater Then Or Equal To
0100 LT Less Then
0101 LEQ Less Then Or Equal To
0110 HI Higher
0111 HIS, C Higher Or Same, Carry Set
1000 LO, NC Lower, Carry Clear
1001 LOS Lower Or Same
1010 NOV No Overflow
1011 OV Overflow
1100 NTC Test Bit Not Set
1101 TC Test Bit Set
1110 NBIO BIO Input Equal To Zero
1111 UNC Unconditional
Return conditionally. If the specified condition is true, a 16-bit value is
popped from the stack and stored into the low 16 bits of the PC while the
upper 6 bits of the PC are forced to 0x3F; Otherwise, execution continues
with the instruction following the XRETC operation:
if(COND = true)
{
SP = SP − 1;
PC = 0x3F:[SP];
}
else
PC = PC + 1;
Note: This instruction can only transfer program control to a location located in the upper 64K
range of program space (0x3F0000 to 0x3FFFFF). To return from a call made by
XCALL, the XRETC instruction must be used. The cycle times for this operation are:
If (COND = true) then the instruction takes 7 cycles.
If (COND = false) then the instruction takes 4 cycles.
If the V flag is tested by the condition, then V is cleared.
This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.
C2xLP Source-Compatible Conditional Return
OPCODE OBJMODE RPT CYC
1 − 4/7
Flags Tested
Z = 0
Z = 1
Z = 0 AND N = 0
N = 0
N = 1
Z = 1 OR N = 1
C = 1 AND Z = 0
C = 1
C = 0
C = 0 OR Z = 1
V = 0
V = 1
TC = 0
TC = 1
BIO = 0
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