DSP Core Reference Manual

Static Programming Rules
SC140 DSP Core Reference Manual 7-13
Rule G.P.3
The following instructions in each line are mutually exclusive, and cannot be grouped in a VLES. For
mutually exclusive IFc subgroups in a VLES, this rule applies independently to each subgroup.
• MARK
• DEBUG and DEBUGEV
• DI and EI
• BREAK, CONT, CONTD, DOENn, DOENSHn, and SKIPLS
STOP, WAIT, and any COF instruction cannot be grouped in a VLES. This applies also to a VLES having
two mutually exclusive IFc subgroups.
Example 7-18. VLES Has Mutually Exclusive Instructions
stop wait ;not allowed
mark mark ;not allowed
stop mark ;allowed
ift doen1 #5 iff doen2 #4 ;allowed
ift debug iff debugev ;allowed
ift stop iff wait ;not allowed
ift wait iff bra _label ;not allowed
Rule G.P.4
An RTE/D instruction cannot be:
• Grouped in a VLES with another AGU instruction.
• In a VLES having two IFc subgroups.
Example 7-19. RTE Uses Both AAU
rted inca r3 ;not allowed
ift clr d0 ifa rte ;not allowed - two IFc subgroups
ift rte impy d0,d1,d2 ;allowed - one IFc group
Rule G.P.5
The same Nn or Mn register can be used as a data source operand of a MOVE-like instruction only once in
a VLES. For mutually exclusive IFc subgroups in a VLES, this rule applies independently to each
subgroup.