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comparison doc/manual/callconvs/callconv_sparc.tex @ 0:3e629dc19168

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initial from svn dyncall-1745
author Daniel Adler
date Thu, 19 Mar 2015 22:24:28 +0100
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1 %//////////////////////////////////////////////////////////////////////////////
2 %
3 % Copyright (c) 2012 Daniel Adler <dadler@uni-goettingen.de>,
4 % Tassilo Philipp <tphilipp@potion-studios.com>
5 %
6 % Permission to use, copy, modify, and distribute this software for any
7 % purpose with or without fee is hereby granted, provided that the above
8 % copyright notice and this permission notice appear in all copies.
9 %
10 % THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 % WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 % MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 % ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 % WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 % ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 % OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 %
18 %//////////////////////////////////////////////////////////////////////////////
19
20 \subsection{SPARC Calling Convention}
21
22 \paragraph{Overview}
23
24 The SPARC family of processors is based on the SPARC instruction set architecture, which comes in basically tree revisions,
25 V7, V8 and V9. The former two are 32-bit whereas the latter refers to the 64-bit SPARC architecture (see next chapter). SPARC is big endian.
26
27 \paragraph{\product{dyncall} support}
28
29 \product{dyncall} fully supports the SPARC 32-bit instruction set (V7 and V8), \product{dyncallback} support is missing, though.
30
31 \subsubsection{SPARC (32-bit) Calling Convention}
32
33 \paragraph{Register usage}
34
35 \begin{itemize}
36 \item 32 32-bit integer/pointer registers
37 \item 32 floating point registers (usable as 8 quad precision, 16 double precision or 32 single precision registers)
38 \item 32 registers are accessible at a time (8 are global ones (g*), whereas the rest forms a register window with 8 input (i*), 8 output (o*) and 8 local (l*) ones)
39 \item invoking a function shifts the register window, the old output registers become the new input registers (old local and input ones are not accessible anymore)
40 \end{itemize}
41
42 \begin{table}[h]
43 \begin{tabular}{lll}
44 \hline
45 Name & Alias & Brief description\\
46 \hline
47 {\bf \%g0} & & Read-only, hardwired to 0 \\
48 {\bf \%g1-\%g7} & & Global \\
49 {\bf \%o0 and \%i0} & & Output and input argument 0, return value \\
50 {\bf \%o1-\%o5 and \%i1-\%i5} & & Output and input argument registers \\
51 {\bf \%o6 and \%i6} & & Stack and frame pointer \\
52 {\bf \%o7 and \%i7} & & Return address (caller writes to o7, callee uses i7) \\
53 \end{tabular}
54 \caption{Register usage on sparc calling convention}
55 \end{table}
56
57 \paragraph{Parameter passing}
58 \begin{itemize}
59 \item Stack parameter order: right-to-left @@@ really?
60 \item Caller cleans up the stack @@@ really?
61 \item Stack always aligned to 8 bytes.
62 \item first 6 integers and floats are passed independently in registers using \%o0-\%o5
63 \item for every other argument the stack is used
64 \item @@@ what about floats, 64bit integers, etc.?
65 \item results are returned in \%i0, and structs/unions pass a pointer to them as a hidden stack parameter (see below)
66 \end{itemize}
67
68 \paragraph{Stack layout}
69
70 Stack directly after function prolog:\\
71
72 \begin{figure}[h]
73 \begin{tabular}{5|3|1 1}
74 \hhline{~-~~}
75 & \vdots & & \\
76 \hhline{~=~~}
77 local data & & & \mrrbrace{10}{caller's frame} \\
78 \hhline{~-~~}
79 padding & & & \\
80 \hhline{~-~~}
81 \mrlbrace{7}{parameter area} & argument x & \mrrbrace{3}{stack parameters} & \\
82 & \ldots & & \\
83 & argument 6 & & \\
84 & input argument 5 spill & \mrrbrace{3}{spill area} & \\
85 & \ldots & & \\
86 & input argument 0 spill & & \\
87 & struct/union return pointer & & \\
88 \hhline{~-~~}
89 register save area (\%i* and \%l*) & & & \\
90 \hhline{~=~~}
91 local data and padding & & & \mrrbrace{3}{current frame} \\
92 \hhline{~-~~}
93 parameter area & & & \\
94 \hhline{~-~~}
95 & \vdots & & \\
96 \hhline{~-~~}
97 \end{tabular}
98 \\
99 \\
100 \\
101 \caption{Stack layout on sparc calling convention}
102 \end{figure}
103