Chapter 11. Alpha Dependent Features

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!lituse_base!N

Used with any memory format instruction (e.g.

ldl

) to indicate that the literal is used for an

address load. The offset field of the instruction must be zero. During relaxation, the code may be

altered to use a gp relative load.

!lituse_jsr!N

Used with a register branch format instruction (e.g.

jsr

) to indicate that the literal is used for a

call. During relaxation, the code may be altered to use a direct branch (e.g.

bsr

).

!lituse_bytoff!N

Used with a byte mask instruction (e.g.

extbl

) to indicate that only the low 3 bits of the address

are relevant. During relaxation, the code may be altered to use an immediate instead of a register

shift.

!lituse_addr!N

Used with any other instruction to indicate that the original address is in fact used, and the original

ldq

instruction may not be altered or deleted. This is useful in conjunction with

lituse_jsr

to

test whether a weak symbol is defined.

ldq

$27,foo($29)

!literal!1

beq

$27,is_undef

!lituse_addr!1

jsr

$26,($27),foo

!lituse_jsr!1

!lituse_tlsgd!N

Used with a register branch format instruction to indicate that the literal is the call to

__tls_get_addr

used to compute the address of the thread local storage variable whose

descriptor was loaded with

!tlsgd!N

.

!lituse_tlsldm!N

Used with a register branch format instruction to indicate that the literal is the call to

__tls_get_addr

used to compute the address of the base of the thread local storage block for

the current module. The descriptor for the module must have been loaded with

!tlsldm!N

.

!gpdisp!N

Used with

ldah

and

lda

to load the GP from the current address, a la the

ldgp

macro. The

source register for the

ldah

instruction must contain the address of the

ldah

instruction. There

must be exactly one

lda

instruction paired with the

ldah

instruction, though it may appear

anywhere in the instruction stream. The immediate operands must be zero.

bsr

$26,foo

ldah $29,0($26)

!gpdisp!1

lda

$29,0($29)

!gpdisp!1

!gprelhigh

Used with an

ldah

instruction to add the high 16 bits of a 32 bit displacement from the GP.

!gprellow

Used with any memory format instruction to add the low 16 bits of a 32 bit displacement from

the GP.

!gprel

Used with any memory format instruction to add a 16 bit displacement from the GP.