HP UX Developer Tools manual Allow Directive, Discussion

Page 58

NOTE

Assembler Directives and Pseudo-Operations

.ALLOW Directive

.ALLOW Directive

The .ALLOW directive tells the Assembler to temporarily allow PA-RISC features from a higher version level of the PA-RISC architecture. The

.ALLOW directive also tells the Assembler to temporarily allow implementation-speciﬁc features in the assembly source ﬁle.

Syntax

.ALLOW 1.1

Lines of source code

.ALLOW

Parameters

1.1Allows PA-RISC 1.1 features.

2.0Allows PA-RISC 2.0 features.

Discussion

Use the .ALLOW directive with the .LEVEL directive. The Assembler uses the .LEVEL directive to mark the relocatable object ﬁle with the proper PA-RISC architecture version level. In the source ﬁle, the Assembler emits warning messages whenever a feature is used that is not appropriate for the speciﬁed .LEVEL directive.

Use the .ALLOW directive when it is necessary to include features or instructions from a later version of PA-RISC while leaving the relocatable object ﬁle marked as an earlier PA-RISC architecture version. For example, use the .ALLOW directive when you need to include PA-RISC 2.0 features or instructions while leaving the relocatable object ﬁle marked as a PA-RISC 1.1 architecture version.

A 2.0W parameter is not permitted with .ALLOW, because the code generated for 2.0W(64-bit mode) is incompatible with other levels.

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Chapter 4

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Contents HP 9000 Computers 92432-90012 JuneRestricted Rights Legend Legal NoticesHanover Street Palo Alto, California Contents Assembler Directives and Pseudo-Operations Contents Contents Contents Contents Pseudo-Instruction Set Assembling Your Program Programming Examples Diagnostic MessagesIndex Printing History PrefaceEdition Date Software Version Audience Related DocumentationTypographical Conventions This ManualSummary of Technical Changes for HP-UX Assembly Language Assembler FeaturesAssembler Features Summary of Changes for PA-RISC Summary of Changes for PA-RISCSummary of Changes for PA-RISC 2.0W Wide Mode, 64-bit ChapterSummary of Changes for PA-RISC 2.0W Wide Mode, 64-bit Program Structure Program Structure Label Opcode Operands CommentsSymbols and Constants Symbols and ConstantsInteger Constants Signed Unsigned Registers and Register Mnemonics Registers and Register MnemonicsRegisters by using an L or R sufﬁx General Registers Single-Precision Floating-Point Registers Space Registers Double-Precision Floating-Point RegistersControl Registers Synonyms Register Procedure Calling Conventions Register Synonyms DescriptionStandard Arithmetic Operators ExpressionsExpressions Operator OperationLegal Combinations For Relocatable Terms Operation Result Available Field Selectors Meaning Field Meaning Selector Multiple of 2048 allows a three-instruction sequence Parenthesized Subexpressions Operands and Completers Operands and CompletersAddi Deﬁning New Instructions With Macros Macro ProcessingMacro Processing Contains general register 19, or binary 10011. These HP-UX Architecture Conventions SpacesSpaces Memory Layout on HP-UX Sr4 Sr5 Sr6 Attributes SubspacesSubspaces Standard Subspaces and Sort Keys DirectivesSpace Subspace Sort Key Use Sections in 64-bit Mode Sections in 64-bit Mode$INIT$ Location Counters Location CountersCompiler Conventions Compiler ConventionsCompiler Conventions Global Symbol Usage Mfctl Shared Libraries Assembly ListingShared Libraries Assembly Listing Assembler Directives IntroductionDirective Function Requests common storage for a speciﬁed number Bytes Pseudo-Operations Directive Function Reserves 16 bits a half word of storage Parameters Align DirectiveSyntax ExampleDiscussion Allow DirectiveAllow Directive To the .LEVEL speciﬁed for the ﬁle Block and .BLOCKZ Pseudo-Operations Block and .BLOCKZ Pseudo-OperationsSpace $TEXT$ Subspa $CODE$ Block Byte Pseudo-Operation Byte Pseudo-OperationByte initvalue , initvalue Call Directive Call DirectiveCall argumentdescription argumentdescription ﬁrst word in the argument list Form of argument-description is Arg=location Where arg canReturn value for a procedure Second word in the argument listLIT Align Word Procend Export Callinfo Directive Callinfo DirectiveCallinfo parameter , parameter Register ENTRYSR= Unwound It restores the RP value when it encounters a .LEAVE Callinfo Directive Stack Frames Re-enter code subspace Label .COMM numbytes Comm DirectiveComm Directive Label Labels the location of the reserved storageCopyright Directive Copyright DirectiveCompany-name Proc Callinfo Enter Double Pseudo-Operation Integer .fraction E powerFraction E power Double Pseudo-OperationDword Pseudo-Operation Dword Pseudo-OperationDword initvalue , initvalue END Directive END DirectiveEndm Directive Endm DirectiveEnter and .LEAVE Pseudo-Operations Enter and .LEAVE Pseudo-OperationsSpace $TEXT$ Entry and .EXIT Directives Entry and .EXIT DirectivesEQU Directive Symbolicname .EQU valueEQU Directive ValueExport Directive Export DirectiveArgument Export proc,ENTRY,ARGW0=GR Float Pseudo-Operation Float Pseudo-OperationHalf Pseudo-Operation Half Pseudo-OperationHalf initvalue , initvalue Import Directive Import DirectiveNOP END Label labelid Label DirectiveLabel Directive Labelid Names the label identiﬁerLevel Directive Level DirectiveLevel Directive Listoff and .LISTON Directives Listoff and .LISTON DirectivesListon Code Space $TEXT$ SPNUM=0,SORT=0 Subspa $CODE$ Locct Directive Locct DirectiveMacro Directive Macro DirectiveLabel .MACRO formalparameter,formalparameter Examples 100 Origin Directive Origin DirectiveChapter 101 Proc and .PROCEND Directives Proc and .PROCEND Directives102 Chapter 103 Label .REG typedregister REG DirectiveREG Directive Label User-deﬁned register nameShlibversion Directive Shlibversion DirectiveChapter 105 Space Directive Space Directive106 Chapter 107 Spnum Pseudo-Operation Spnum Pseudo-Operation108 String and .STRINGZ Pseudo-Operations String and .STRINGZ Pseudo-OperationsChapter 109 110 Name An identiﬁer that names the current subspace Subspa DirectiveSubspa Directive Chapter 111112 Chapter 113 Version Directive Version Directive114 Word initvalue , initvalue Word Pseudo-OperationWord Pseudo-Operation Chapter 115Programming Aids Directive Space Name Default ParametersProgramming Aids Predeﬁned Subspace DirectivesShortdata Chapter 117Programming Aids 118 Pseudo-Instruction Set 119120 Cond Description Compare and Branch Conditions Comb and ComibChapter 121 Add and Branch Conditions Addb and Addib Description 122Invoking the Assembler 123Assemble code for the architecture Using the as CommandUsing the as Command 124Level ﬁlenameChapter 125 Online User Guide WnumberTables, see HP-UX Linker and Libraries 126Passing Arguments to the Assembler Using the cc CommandUsing the cc Command Wa, ,as-argument as-argumentCpp Preprocessor 128Programming Examples 129Binary Search for Highest Bit Position Binary Search for Highest Bit Position130 Chapter 131 Copying a String Copying a String132 Chapter 133 Dividing a Double-Word Dividend Dividing a Double-Word Dividend134 Programming Examples Chapter 135Program Listing Demonstrating the Procedure Calling ConventionDemonstrating the Procedure Calling Convention 136Assembly Program Listing Chapter 137Output of the cc -S Command Output of the cc -S CommandAssembly Program Listing From the C Compiler 138Chapter 139 Output of the cc -S Command 140 141 Option operand 142Chapter 143 Reserve 144Use a general register Wrong register type usedChapter 145 Use a control register Use a space register146 Chapter 147 148 Chapter 149 150 Chapter 151 Used to invoke the assembler 152Chapter 153 Error Messages Error Messages154 Chapter 155 156 Chapter 157 158 1029 10271028 10301033 10311032 10341037 10351036 1038162 Chapter 163 1056 10541055 1057Chapter 165 166 Chapter 167 168 1081 Format keyword=value1080 1082170 1090 10881089 Chapter 1711095 10911094 10961099 10971098 11001103 11011102 11041105 Chapter 175Panic Messages Panic Messages176 2007 20052006 2008User Warning Messages User Warning Messages178 7005 70037004 7006180 Chapter 181 182 7200 Limit Error MessagesLimit Error Messages 72017204 72027203 184Diagnostic Messages Chapter 185186 Branching Error Messages Branching Error MessagesChapter 187 188 Chapter 189 190 Chapter 191 192 7834 78277828 7835Expr 78367837 194Index Index 195196 NumericsIndex 197 Copyright198 HP C/HP-UX,49Index 199 Mfctl200 DoubleIndex 201 See also memory202

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