ELF relocations are available as defined in the 32-bit and 64-bit Sparc ELF specifications.
R_SPARC_HI22 is obtained using ‘%hi’ and R_SPARC_LO10
is obtained using ‘%lo’. Likewise R_SPARC_HIX22 is
obtained from ‘%hix’ and R_SPARC_LOX10 is obtained
using ‘%lox’. For example:
sethi %hi(symbol), %g1 or %g1, %lo(symbol), %g1 sethi %hix(symbol), %g1 xor %g1, %lox(symbol), %g1
These “high” mnemonics extract bits 31:10 of their operand, and the “low” mnemonics extract bits 9:0 of their operand.
V9 code model relocations can be requested as follows:
R_SPARC_HH22 is requested using ‘%hh’. It can
also be generated using ‘%uhi’.
R_SPARC_HM10 is requested using ‘%hm’. It can
also be generated using ‘%ulo’.
R_SPARC_LM22 is requested using ‘%lm’.
R_SPARC_H44 is requested using ‘%h44’.
R_SPARC_M44 is requested using ‘%m44’.
R_SPARC_L44 is requested using ‘%l44’ or ‘%l34’.
R_SPARC_H34 is requested using ‘%h34’.
The ‘%l34’ generates a R_SPARC_L44 relocation because it
calculates the necessary value, and therefore no explicit
R_SPARC_L34 relocation needed to be created for this purpose.
The ‘%h34’ and ‘%l34’ relocations are used for the abs34 code model. Here is an example abs34 address generation sequence:
sethi %h34(symbol), %g1 sllx %g1, 2, %g1 or %g1, %l34(symbol), %g1
The PC relative relocation R_SPARC_PC22 can be obtained by
enclosing an operand inside of ‘%pc22’. Likewise, the
R_SPARC_PC10 relocation can be obtained using ‘%pc10’.
These are mostly used when assembling PIC code. For example, the
standard PIC sequence on Sparc to get the base of the global offset
table, PC relative, into a register, can be performed as:
sethi %pc22(_GLOBAL_OFFSET_TABLE_-4), %l7 add %l7, %pc10(_GLOBAL_OFFSET_TABLE_+4), %l7
Several relocations exist to allow the link editor to potentially
optimize GOT data references. The R_SPARC_GOTDATA_OP_HIX22
relocation can obtained by enclosing an operand inside of
‘%gdop_hix22’. The R_SPARC_GOTDATA_OP_LOX10
relocation can obtained by enclosing an operand inside of
‘%gdop_lox10’. Likewise, R_SPARC_GOTDATA_OP can be
obtained by enclosing an operand inside of ‘%gdop’.
For example, assuming the GOT base is in register %l7:
sethi %gdop_hix22(symbol), %l1 xor %l1, %gdop_lox10(symbol), %l1 ld [%l7 + %l1], %l2, %gdop(symbol)
There are many relocations that can be requested for access to thread local storage variables. All of the Sparc TLS mnemonics are supported:
R_SPARC_TLS_GD_HI22 is requested using ‘%tgd_hi22’.
R_SPARC_TLS_GD_LO10 is requested using ‘%tgd_lo10’.
R_SPARC_TLS_GD_ADD is requested using ‘%tgd_add’.
R_SPARC_TLS_GD_CALL is requested using ‘%tgd_call’.
R_SPARC_TLS_LDM_HI22 is requested using ‘%tldm_hi22’.
R_SPARC_TLS_LDM_LO10 is requested using ‘%tldm_lo10’.
R_SPARC_TLS_LDM_ADD is requested using ‘%tldm_add’.
R_SPARC_TLS_LDM_CALL is requested using ‘%tldm_call’.
R_SPARC_TLS_LDO_HIX22 is requested using ‘%tldo_hix22’.
R_SPARC_TLS_LDO_LOX10 is requested using ‘%tldo_lox10’.
R_SPARC_TLS_LDO_ADD is requested using ‘%tldo_add’.
R_SPARC_TLS_IE_HI22 is requested using ‘%tie_hi22’.
R_SPARC_TLS_IE_LO10 is requested using ‘%tie_lo10’.
R_SPARC_TLS_IE_LD is requested using ‘%tie_ld’.
R_SPARC_TLS_IE_LDX is requested using ‘%tie_ldx’.
R_SPARC_TLS_IE_ADD is requested using ‘%tie_add’.
R_SPARC_TLS_LE_HIX22 is requested using ‘%tle_hix22’.
R_SPARC_TLS_LE_LOX10 is requested using ‘%tle_lox10’.
Here are some example TLS model sequences.
First, General Dynamic:
sethi %tgd_hi22(symbol), %l1 add %l1, %tgd_lo10(symbol), %l1 add %l7, %l1, %o0, %tgd_add(symbol) call __tls_get_addr, %tgd_call(symbol) nop
Local Dynamic:
sethi %tldm_hi22(symbol), %l1 add %l1, %tldm_lo10(symbol), %l1 add %l7, %l1, %o0, %tldm_add(symbol) call __tls_get_addr, %tldm_call(symbol) nop sethi %tldo_hix22(symbol), %l1 xor %l1, %tldo_lox10(symbol), %l1 add %o0, %l1, %l1, %tldo_add(symbol)
Initial Exec:
sethi %tie_hi22(symbol), %l1 add %l1, %tie_lo10(symbol), %l1 ld [%l7 + %l1], %o0, %tie_ld(symbol) add %g7, %o0, %o0, %tie_add(symbol) sethi %tie_hi22(symbol), %l1 add %l1, %tie_lo10(symbol), %l1 ldx [%l7 + %l1], %o0, %tie_ldx(symbol) add %g7, %o0, %o0, %tie_add(symbol)
And finally, Local Exec:
sethi %tle_hix22(symbol), %l1 add %l1, %tle_lox10(symbol), %l1 add %g7, %l1, %l1
When assembling for 64-bit, and a secondary constant addend is
specified in an address expression that would normally generate
an R_SPARC_LO10 relocation, the assembler will emit an
R_SPARC_OLO10 instead.