Vax performance V-008 SP User's Guide download pdf (Page 141)

MACRO Compiler Built-ins

This appendix describes the built-ins provided with the MACRO Compiler for

OpenVMS Systems.

On OpenVMS Alpha systems, the compiler provides two sets of built-ins:

• Alpha instruction built-ins that are used to access Alpha instructions for

which there are no VAX equivalents. (See Section C.1.)

• Alpha PALcode built-ins that are used to emulate the VAX instructions for

which there are no Alpha equivalents and to perform other functions such as

quadword queue manipulations. (See Section C.2.)

On OpenVMS I64 systems, the compiler provides two sets of built-ins:

• Alpha instruction built-ins that are used to generate Itanium instructions for

which there are no VAX equivalents. (See Section C.1.)

• Itanium instruction built-ins that are used to access Itanium instructions for

which there are no VAX equivalents. (See Section C.3.)

On OpenVMS I64 systems, all of the Alpha PALcode built-ins are emulated by

means of macros provided by the system.

Both sets of built-ins are presented in tables. The second column of each table

speciﬁes the operands the built-in expects, where:

WL = write longword

ML = modify longword

AL = address of longword

WQ = write quadword

RQ = read quadword

MQ = modify quadword

AQ = address of quadword

AB = address of byte

AW = address of word

WB = write byte

WW = write word

Note

Be careful when mixing built-ins with VAX MACRO instructions on the

same registers. The code generated by the compiler expects registers

to contain 32-bit sign-extended values, but it is possible to create

64-bit register values that are not in this format. Subsequent longword

operations on these registers could produce incorrect results.

Therefore, make sure to return registers to 32-bit sign-extended format

before using them in VAX MACRO instructions as source operands.

MACRO Compiler Built-ins C–1

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Vax performance V-008 SP User's Guide Page 141