Mercurial > pub > dyncall > dyncall
view doc/manual/callconvs/callconv_sparc32.tex @ 210:087373e6adb3
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author | Tassilo Philipp |
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date | Tue, 28 Mar 2017 15:27:21 +0200 |
parents | e07fb0bbddae |
children | 276eb8c87aa0 |
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%////////////////////////////////////////////////////////////////////////////// % % Copyright (c) 2012-2017 Daniel Adler <dadler@uni-goettingen.de>, % Tassilo Philipp <tphilipp@potion-studios.com> % % Permission to use, copy, modify, and distribute this software for any % purpose with or without fee is hereby granted, provided that the above % copyright notice and this permission notice appear in all copies. % % THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES % WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF % MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR % ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES % WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN % ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF % OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. % %////////////////////////////////////////////////////////////////////////////// \subsection{SPARC Calling Convention} \paragraph{Overview} The SPARC family of processors is based on the SPARC instruction set architecture, which comes in basically tree revisions, V7, V8\cite{SPARCV8}\cite{SPARCSysV} and V9\cite{SPARCV9}\cite{SPARCV9SysV}. The former two are 32-bit whereas the latter refers to the 64-bit SPARC architecture (see next chapter). SPARC uses big endian byte order.\\ \paragraph{\product{dyncall} support} \product{dyncall} fully supports the SPARC 32-bit instruction set (V7 and V8), for calls and callbacks. \subsubsection{SPARC (32-bit) Calling Convention} \paragraph{Register usage} \begin{itemize} \item 32 single floating point registers (f0-f31, usable as 8 quad precision q0,q4,q8,...,q28, 16 double precision d0,d2,d4,...,d30) \item 32 32-bit integer/pointer registers out of a bigger (vendor/model dependent) number that are accessible at a time (8 are global ones (g*), whereas the remaining 24 form a register window with 8 input (i*), 8 output (o*) and 8 local (l*) ones) \item calling a function shifts the register window, the old output registers become the new input registers (old local and input ones are not accessible anymore) \end{itemize} \begin{table}[h] \begin{tabular*}{0.95\textwidth}{lll} Name & Alias & Brief description\\ \hline {\bf \%g0} & \%r0 & Read-only, hardwired to 0 \\ {\bf \%g1-\%g7} & \%r1-\%r7 & Global \\ {\bf \%o0,\%o1 and \%i0,\%i1} & \%r8,\%r9 and \%r24,\%r25 & Output and input argument registers, return value \\ {\bf \%o2-\%o5 and \%i2-\%i5} & \%r10-\%r13 and \%r26-\%r29 & Output and input argument registers \\ {\bf \%o6 and \%i6} & \%r14 and \%r30, \%sp and \%fp & Stack and frame pointer \\ {\bf \%o7 and \%i7} & \%r15 and \%r31 & Return address (caller writes to o7, callee uses i7) \\ {\bf \%l0-\%l7} & \%r16-\%r23 & preserve \\ {\bf \%f0,\%f1} & & Floating point return value \\ {\bf \%f2-\%f31} & & scratch \\ \end{tabular*} \caption{Register usage on sparc calling convention} \end{table} \paragraph{Parameter passing} \begin{itemize} \item stack grows down \item stack parameter order: right-to-left \item caller cleans up the stack \item stack always aligned to 8 bytes \item first 6 integers and floats are passed independently in registers using \%o0-\%o5 \item for every other argument the stack is used \item all arguments \textless=\ 32 bit are passed as 32 bit values \item 64 bit arguments are passed like two consecutive \textless=\ 32 bit values \item minimum stack size is 64 bytes, b/c stack pointer must always point at enough space to store all \%i* and \%l* registers, used when running out of register windows \item if needed, register spill area is adjacent to parameters \item results are expected by caller to be returned in \%o0/\%o1 (after reg window restore, meaning callee writes to \%i0/\%i1) for integers, \%f0/\%f1 for floats, and for structs/unions a pointer to them is used as a hidden stack parameter (see below) \end{itemize} \paragraph{Stack layout} Stack directly after function prolog:\\ \begin{figure}[h] \begin{tabular}{5|3|1 1} \hhline{~-~~} & \vdots & & \\ \hhline{~=~~} local data (and padding) & \hspace{4cm} & & \mrrbrace{9}{caller's frame} \\ \hhline{~-~~} \mrlbrace{7}{parameter area} & argument x & \mrrbrace{3}{stack parameters} & \\ & \ldots & & \\ & argument 6 & & \\ & input argument 5 spill & \mrrbrace{3}{spill area} & \\ & \ldots & & \\ & input argument 0 spill & & \\ & struct/union return pointer & & \\ \hhline{~-~~} register save area (\%i* and \%l*) & & & \\ \hhline{~=~~} local data (and padding) & & & \mrrbrace{3}{current frame} \\ \hhline{~-~~} parameter area & & & \\ \hhline{~-~~} & \vdots & & \\ \hhline{~-~~} \end{tabular} \\ \\ \\ \caption{Stack layout on sparc32 calling convention} \end{figure}