78IV datasheet(29/523 Pages) NEC

29 / 523 page

CHAPTER 1 GENERAL

User’s Manual U15556EJ1V0UM

<3> Using the saddr area

Variables declared with the keyword sreg can be allocated to the saddr area. Instructions to these sreg

variables are shorter in code length than those to memory.

This helps shorten object code and also

improves program execution speed. Variables can be allocated to the saddr area also by option (only to the

saddr2 area).

<4> sfr area

By declaring use of sfr names, manipulations on the sfr area can be described at the C source file.

<5> noauto functions

Functions declared as noauto do not output code for preprocessing and postprocessing (stack frame

formation). By calling a noauto function, arguments are passed via registers. This helps shorten object

code and improve program execution speed as well. This function has restrictions on arguments/automatic

variables. For the details, refer to 11.5 (5) noauto function.

<6> norec/_ _leaf functions

Functions declared as norec/_ _leaf do not output code for preprocessing and postprocessing (stack frame

formation). By calling a norec/_ _leaf function, arguments are passed via registers as much as possible.

Automatic variables to be used inside a norec/_ _leaf function are allocated to register or the saddr area.

This helps shorten object code and also improve program execution speed. This function has restrictions on

arguments/automatic variables and is not allowed to call a function. For the details, refer to 11.5 (6) norec

function.

<7> bit type variables and boolean/_ _boolean type variables

Variables with a 1-bit storage area are generated. By using the bit type variable or boolean/_ _ boolean

type variable, the saddr2 area can be accessed in bit units.

The boolean/_ _boolean type variable is the same as the bit type variable in terms of both function and

usage.

<8> boolean1 type variables

Variables with a 1-bit storage area are generated. By using the _ _ boolean1 type variable, the saddr1 area

can be accessed in bit units.

The _ _boolean1 type variable is the same as the bit type variable in terms of both function and usage.

<9> ASM statements

The assembler source program described by the user can be embedded in an assembler source file to be

output by this C compiler.

<10> Interrupt functions

A vector table and an object code corresponding to the interrupt are output. This allows programming of

interrupt functions at the C source level.

<11> Interrupt function qualifier

This qualifier allows the setting of a vector table and interrupt function definitions to be described in a

separate file.

78IV Datasheet(PDF) 29 Page - NEC