CC78K4 Datasheet, PDF (484/523 Pages) NEC – CC78K4 Ver.2.30 or Later, C Compiler Language

CHAPTER 13 EFFECTIVE UTILIZATION OF COMPILER
This chapter introduces how to effectively use this C compiler.
13.1 Efficient Coding
When developing 78K/IV Series microcontroller-applied products, efficient object generation may be realized with
this C compiler by utilizing the saddr1/2 area, callt table, or callf area of the device.
Use of external variables
if (saddr2 area can be used)
Use sreg/_ _sreg variables/use compiler option (-RD).
if (saddr1 area can be used)
Use _ _sreg1 variables.
Use of bit type (one bit) data
if (saddr2 area can be used)
Use bit/boolean/_ _boolean type variables.
if (saddr1 area can be used)
Use _ _boolean1 type variables.
Definition of function
if (the function is to be called frequently)
if (callt table can be used)
Declare it as _ _callt/callt function.
(Effective to shorten the code size)
if (callf area can be used)
Declare it as _ _callf/callf function.
(Effective to improve the execution speed)
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User’s Manual U15556EJ1V0UM