From: Simon Marchi Date: Fri, 8 Sep 2023 15:20:58 +0000 (-0400) Subject: gdb/doc: describe x87 registers X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=15db2284f2f8259e46635ca6df3efc772d951fac;p=binutils-gdb.git gdb/doc: describe x87 registers While investigating this [1], I initially had no idea what register "fioff" stood for, making it difficult to map it to something in the Intel or AMD manuals. Similarly, I can imaging someone familiar with x87 to want to print the "x87 last instruction address", and have no clue that GDB makes it available as register "fioff". The names of the x87 state fields don't seem to be standardized, they even change between sections of the Intel manual (between the FSAVE, FXSAVE and XSAVE area descriptions). Add some details to the doc to help one map GDB register names to x87 state fields. [1] https://inbox.sourceware.org/gdb-patches/20230908022722.430741-1-simon.marchi@efficios.com/T/#u Change-Id: I0ea1eb648358e62da4aa87eea3515ee8a09f2762 Approved-By: Eli Zaretskii Approved-By: Pedro Alves --- diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 72083fc5b64..9b7e06f3156 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -26310,6 +26310,25 @@ At this last step the value of bnd0 can be changed for investigation of bound violations caused along the execution of the call. In order to know how to set the bound registers or bound table for the call consult the ABI. +@subsubsection x87 registers + +@value{GDBN} provides access to the x87 state through the following registers: + +@itemize + +@item @code{$st0} to @code{st7}: @code{ST(0)} to @code{ST(7)} floating-point +registers +@item @code{$fctrl}: control word register (@code{FCW}) +@item @code{$fstat}: status word register (@code{FSW}) +@item @code{$ftag}: tag word (@code{FTW}) +@item @code{$fiseg}: last instruction pointer segment +@item @code{$fioff}: last instruction pointer +@item @code{$foseg}: last data pointer segment +@item @code{$fooff}: last data pointer +@item @code{$fop}: last opcode + +@end itemize + @node Alpha @subsection Alpha