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SEMI P39-0304 E2 © SEMI 2004 15 15 CELLNAME Record 15.1 A CELLNAME record associates the name of a cell w ith a unique refere nce number. This allows CELL and PLACEMENT records , if desired, to avoid redundantl y storing…

SEMI P39-0304

located discontiguously from its tabular group should be treated as a fatal error, and any records which fail to use

reference-number access for that class of objects should be treated as a fatal error. An OASIS reader which does not

rely on any of the record grouping, reference-number, and byte-offset guarantees provided by strict mode is not

required to detect and report any exceptions related to strict mode.

14 END Record

14.1 An END record identifies the end of the OASIS file. The END record must be the last record in the file; no

trailing bytes are permitted. It has the following format:

‘2’ [ table-offsets ] padding-string validation-scheme [ validation-signature ]

14.2 The presence of the table-offsets structure is governed by offset-flag in the START record (see Section 13 on

page 13). The padding-string (a b-string) must be sized and inserted by the OASIS writer so that the total byte

length of the END record, including the record-ID, is exactly 256 bytes. This makes it possible for an OASIS reader

to find the END record (and any table-offsets and validation-signature) using a relative seek from the logical end-

of-file, avoiding the need to store a forward pointer in the START record. The contents of padding-string should

be initialized to NUL characters.

14.3 validation-scheme is an unsigned-integer which selects the validation scheme used, and validation-signature

is an optional scheme-dependent group of bytes used for validating the integrity of the OASIS file. The following

validation schemes are defined:

Table 12 END Record Validation Schemes

Scheme Description Validation Signature Length

0 No Validation 0

1 CRC32 4

2 CHECKSUM32 4

14.4 CRC32 Validation

14.4.1 The CRC32 polynomial is specified in ISO 3309:

+ x

With the left-most bit representing the most significant bit, this corresponds to a value of:

binary 1 0000 0100 1100 0001 0001 1101 1011 0111

hexadecimal 104c11db7

14.4.2 The CRC32 value is computed using all of the bytes in the OASIS file from the first byte of the START

record to the END record’s validation-scheme integer. It is byte-order dependent. The resulting 32-bit word is

stored in the last 4 bytes of the file, with the least significant byte first. This calculation is usually implemented

using a table-lookup shift/XOR method. See Appendix 1 for sample C-language source code.

14.5 CHECKSUM32 Validation

14.5.1 The CHECKSUM32 validation signature is computed as a simple unsigned arithmetic summation of all of

the bytes in the OASIS file from the first byte of the START record to the END record’s validation-scheme

integer. This value is then truncated to its least significant 32 bits and stored in the last 4 bytes of the file, with the

least significant byte first. It is not byte-order dependent, and this characteristic makes it somewhat easier to

calculate if the file is not written sequentially. It is, however, far less effective than CRC32 for detecting errors. See

Appendix 1 for sample C-language source code.

14.6 EXCEPTION HANDLING

— OASIS processors should treat the absence of an END record in an OASIS file

as a fatal error.

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15 CELLNAME Record

15.1 A CELLNAME record associates the name of a cell with a unique reference number. This allows CELL and

PLACEMENT records, if desired, to avoid redundantly storing the actual text of the cell name and instead refer to

the cell by its assigned reference number. It has the following format:

‘3’ cellname-string

‘4’ cellname-string reference-number

15.2 cellname-string is an n-string which holds the cell name. The reference-number is an unsigned-integer

which is either implicitly or explicitly assigned to the cell. Implicit assignment occurs in record type ‘3’, by

assigning sequential reference numbers beginning with 0 as each successive CELLNAME record is encountered.

Explicit assignment occurs in record type ‘4’.

15.3 Two standard properties, S_BOUNDING_BOX and S_CELL_OFFSET (described in Section A2-2 on page

36), may be associated with each CELLNAME record. When all CELLNAME records have been grouped into a

single contiguous table in strict mode (as described in Section 13 on page 13), with an S_CELL_OFFSET property

for every CELLNAME record, the table forms a complete index of all cells in the OASIS file, suitable for random

access.

15.4 Record types ‘3’ and ‘4’ may not both be used in the same OASIS file.

15.5 EXCEPTION HANDLING

— The appearance of two CELLNAME records in the same file with the same

number but different names, or two CELLNAME records in the same file with the same name but different

numbers, should be treated as a fatal error. The appearance of both record types ‘3’ and ‘4’ in the same OASIS file

should be treated as a fatal error. The presence of more than one S_CELL_OFFSET or S_BOUNDING_BOX

property after a given CELLNAME record should be treated as a fatal error.

16 TEXTSTRING Record

16.1 A TEXTSTRING record associates a text string with a unique reference number. This allows TEXT records,

if desired, to avoid redundantly storing the actual text of the string and instead refer to the string by its assigned

reference number. It has the following format:

‘5’ text-string

‘6’ text-string reference-number

16.2 text-string is an a-string which holds the text string. The reference-number is an unsigned-integer which is

either implicitly or explicitly assigned to the text string. Implicit assignment occurs in record type ‘5’, by assigning

sequential reference numbers beginning with 0 as each successive TEXTSTRING record is encountered. Explicit

assignment occurs in record type ‘6’.

16.3 Record types ‘5’ and ‘6’ may not both be used in the same OASIS file.

16.4 EXCEPTION HANDLING

— The appearance of two TEXTSTRING records in the same file with the same

number but different names, or two TEXTSTRING records in the same file with the same name but different

numbers, should be treated as a fatal error. The appearance of both record types ‘5’ and ‘6’ in the same OASIS file

should be treated as a fatal error.

17 PROPNAME Record

17.1 A PROPNAME record associates the name of a property with a unique reference number. This allows

PROPERTY records, if desired, to avoid redundantly storing the actual text of the property name and instead refer

to the property name by its assigned reference number. It has the following format:

‘7’ propname-string

‘8’ propname-string reference-number

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17.2 propname-string is an n-string which holds the property name. The reference-number is an unsigned-

integer which is either implicitly or explicitly assigned to the property name. Implicit assignment occurs in record

type ‘7’, by assigning sequential reference numbers beginning with 0 as each successive PROPNAME record is

encountered. Explicit assignment occurs in record type ‘8’.

17.3 Record types ‘7’ and ‘8’ may not both be used in the same OASIS file.

17.4 EXCEPTION HANDLING

— The appearance of two PROPNAME records in the same file with the same

number but different names, or two PROPNAME records in the same file with the same name but different

numbers, should be treated as a fatal error. The appearance of both record types ‘7’ and ‘8’ in the same OASIS file

should be treated as a fatal error.

18 PROPSTRING Record

18.1 A PROPSTRING record associates a property string with a unique reference number. This allows

PROPERTY records, if desired, to avoid redundantly storing the actual text of the property string and instead refer

to the property string by its assigned reference number. It has the following format:

‘9’ prop-string

‘10’ prop-string reference-number

18.2 prop-string is an a-string, b-string , or n-string which holds the property string, depending on the referencing

PROPERTY record. The reference-number is an unsigned-integer which is either implicitly or explicitly assigned

to the property string. Implicit assignment occurs in record type ‘9’, by assigning sequential reference numbers

beginning with 0 as each successive PROPSTRING record is encountered. Explicit assignment occurs in record

type ‘10’.

18.3 Record types ‘9’ and ‘10’ may not both be used in the same OASIS file.

18.4 EXCEPTION HANDLING

— The appearance of two PROPSTRING records in the same file with the same

number but different names should be treated as a fatal error. The appearance of both record types ‘9’ and ‘10’ in the

same OASIS file should be treated as a fatal error.

19 LAYERNAME Record

19.1 A LAYERNAME record provides a means of mapping numeric (layer,datatype) and (layer,texttype)

combinations to layer names. It has the following format:

‘11’ layername-string layer-interval datatype-interval

‘12’ layername-string textlayer-interval texttype-interval

19.2 Record type ‘11’ maps a range of (layer,datatype) numbers to a layer name, and record type ‘12’ maps a range

of (textlayer,texttype) numbers to a layer name.

19.3 layername-string is an n-string containing the layer name.

19.4 Each of the interval fields consists of an unsigned-integer denoting the interval type, followed by 0, 1, or 2

unsigned-integers representing the bounds of that interval as follows:

Table 13 LAYERNAME Interval Types

Type Bounds Implied Range

0 to  

bound-a

0 to bound-a

bound-a

bound-a to 

bound-a bound-a

bound-a bound-b

bound-a to bound-b