apple-pascal-1.3-manual

4: SEPRTSEG. Separately assembled procedures or functions, includingEXTERNAL functions and procedures, and mixed segments of linkedPascal and assembly-language code. Assembly-language codefiles arealways of this type.5: UNLINKED-INTRINS. An Intrinsic Unit containing unresolved calls toassembly-language procedures or functions.6: LINKED-INTRINS. An Intrinsic Unit properly linked with its calledprocedures and functions.7: DATASEG. A data segment of an Intrinsic Unit. The segmentdictionary entry specifies the amount of data space (in bytes) toallocate.The TEXTADDR array of integers contains pointers to the block number ofthe start of the interface text of each Regular or Intrinsic Unit. The lastblock number of the interface text can be calculated by subtracting 1 fromthe value in the corresponding CODEADDR field. Interface text is describedin detail below. Only unit segments have interface text; the TEXTADDRfield is 0 for all other types of segments.The SEGINFO array contains one word of additional information about eachsegment. Each word is composed of four fields:o Bits 0 through 7 (the low-order byte) of each word specify the segmentnumber (SEGNUM). This is the position the code segment will occupy inthe segment table at execution time. In the 128K system the segmenttable is 64 entries long, hence valid numbers for the SEGNUM field are0 .. 63. In the 64K system the segment table is 32 entries long, hence validnumbers for the SEGNUM field are 0 .. 31. Segment tables are described inChapter 3.o Bits 8 through 11 of the second byte in the SEGINFO word specify themachine type (MTYPE) of the code in the segment. The machine typesare:0: Unidentified code, perhaps from another Compiler.1: P-code, most significant byte first.2: P-code, least significant byte first (a stream of packed ASCIIcharacters fills the low byte of a word first, then the high byte).This kind of P-code is used by the Apple II family.3 through 9: Assembled native code, produced fromassembly-language text. Machine type 7 identifiesnative code for the 6502 microprocessor.IV-26Chapter 2: Disk Files