ST9 datasheet(121/146 Pages) STMICROELECTRONICS

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ST9 USER GUIDE

.fardata : AT (LOADADDR(.data) + SIZEOF (.data))

{ *(.fardata) }> RAM

.reg16_data :AT (LOADADDR(.fardata) + SIZEOF (.fardata))

{ *(.reg16_data)}

> REGFILE

.reg16_bss :

{ *(.reg16_bss)}

> REGFILE

.reg8_data :AT (LOADADDR(.reg16_data) + SIZEOF (.reg16_data))

{ *(.reg8_data) }> REGFILE

.reg8_bss :

{ *(.reg8_bss)}

> REGFILE

}

For more details on the Command File, refer to the Command Language section in the GNU

Software Tools User Manual.

5.4.3 Writing the Start-Up File

This file is the very first file executed at power on. It performs the initialisation procedure re-

quired for the processor to start. It differs according to whether the program includes modules

written in C or not.

In all cases, it includes two main parts:

– The reset, exception and interrupt vectors.

– The initialisation code that is required for the program to start.

5.4.3.1 Vector Table

The vectors consist of the Reset vector, the Divide by zero vector and the other interrupt vec-

tors. They are placed at defined addresses:

– The Reset vector must be located in the first word of the first segment.

– The Divide by zero trap must be placed at address 2 in each segment where a program uses

division. Each segment containing programs using division must have its own Address trap

branched to a local routine making only a “CALLS DIVIDE_BY_ZERO” far call to the Divide

by zero service routine located in a single segment.

ST9 Datasheet(PDF) 121 Page - STMicroelectronics