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21.4.4 MIPS

Alpha- and MIPS-based computers use an unusual stack frame, which sometimes requires gdb to search backward in the object code to find the beginning of a function.

To improve response time (especially for embedded applications, where gdb may be restricted to a slow serial line for this search) you may want to limit the size of this search, using one of these commands:

set heuristic-fence-post limit
Restrict gdb to examining at most limit bytes in its search for the beginning of a function. A value of 0 (the default) means there is no limit. However, except for 0, the larger the limit the more bytes heuristic-fence-post must search and therefore the longer it takes to run. You should only need to use this command when debugging a stripped executable.
show heuristic-fence-post
Display the current limit.

These commands are available only when gdb is configured for debugging programs on Alpha or MIPS processors.

Several MIPS-specific commands are available when debugging MIPS programs:

set mips abi arg
Tell gdb which MIPS ABI is used by the inferior. Possible values of arg are:
auto
The default ABI associated with the current binary (this is the default).
o32
o64
n32
n64
eabi32
eabi64
auto

show mips abi
Show the MIPS ABI used by gdb to debug the inferior.
set mipsfpu
show mipsfpu
See set mipsfpu.
set mips mask-address arg
This command determines whether the most-significant 32 bits of 64-bit MIPS addresses are masked off. The argument arg can be on, off, or auto. The latter is the default setting, which lets gdb determine the correct value.
show mips mask-address
Show whether the upper 32 bits of MIPS addresses are masked off or not.
set remote-mips64-transfers-32bit-regs
This command controls compatibility with 64-bit MIPS targets that transfer data in 32-bit quantities. If you have an old MIPS 64 target that transfers 32 bits for some registers, like sr and fsr, and 64 bits for other registers, set this option to on.
show remote-mips64-transfers-32bit-regs
Show the current setting of compatibility with older MIPS 64 targets.
set debug mips
This command turns on and off debugging messages for the MIPS-specific target code in gdb.
show debug mips
Show the current setting of MIPS debugging messages.