pcp_reference_guide_v2.5 - Tasking

02 ÁÁÁÁ0000 ÁÁÁObject File Formats7−9Byte Type Record type00 Data01 End of File02 Extended segment address (not used)03 Start segment address (not used)04 Extended linear address (32−bit)05 Start linear address (32−bit)contentchecksumis the information contained in the record. This depends onthe record type.is the record checksum. The linker computes the checksumby first adding the binary representation of the previousbytes (from length to content). The linker then computes theresult of sum modulo 256 and subtracts the remainder from256 (two’s complement). Therefore, the sum of all bytesfollowing the header is zero.Extended Linear Address RecordThe Extended Linear Address Record specifies the two most significantbytes (bits 16−31) of the absolute address of the first data byte in asubsequent Data Record::04 upper_addressÁÁÁÁÁÁÁchecksumÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁThe 32−bit absolute address of a byte in a Data Record is calculated as:ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ( address + offset + index ) modulo 4Gwhere:addressoffsetindexis the base address, where the two most significant bytes arethe upper_address and the two least significant bytes arezero.is the 16−bit offset from the Data Record.is the index of the data byte within the Data Record (0 forthe first byte).• • • • • • • •