Port RISC OS support skeleton to Python 3.14

[Copilot]

Establishes RISC OS platform support structure from the riscos branch (Python 3.8.8 base) to enable Python 3.14 builds for RISC OS. Code uses Python 3.8 APIs and requires follow-up API modernization.

Directory Structure

• RISCOS/ - Platform-specific build files, module config, and path handling
  • Makefile - RISC OS build system (updated VERSION=3.14)
  • config.c, pyconfig.h - Module configuration
  • getpath.c - Module search paths with RISC OS conventions
  • swimodule.c - Software Interrupt (SWI) interface
  • RiscPkg-314/ - Package metadata (renamed from RiscPkg-38)
  • _Python3/, _PythonSite/, _PythonUser/ - Boot files and resources

Platform Conditionals

Added #ifdef RISCOS blocks for platform-specific behavior:

Path Handling

• Include/osdefs.h - Path separators: . for directory, , for search paths (RISC OS convention)

Exception Handling

• Include/cpython/pyerrors.h, Objects/exceptions.c - RISCOSError exception type with errnum and errmsg attributes

Build Integration

• Programs/python.c, Programs/_freeze_module.c - Riscosify control flags to handle path translation
• Modules/getbuildinfo.c - Build identifier override ("riscos-1")

Dynamic Loading

• Python/dynload_shlib.c - Extension suffix /so instead of .so, path unixification via __unixify()

System Integration

• Modules/timemodule.c - Sleep via OS_ReadMonotonicTime SWI instead of select()
• Modules/_ssl.c - Certificate path stubs (X509 defaults unused on RISC OS)
• Python/initconfig.c - Config string-to-int parsing stub (returns 0)

API Modernization Required

Module initialization in RISCOS/config.c and RISCOS/swimodule.c uses Python 3.8 patterns. Follow-up work needed to update to Python 3.14 PyModuleDef structure and exception APIs.

Original prompt

Objective

Port the RISC OS-specific changes from the riscos branch (based on Python 3.8.8) to the python-314 branch (Python 3.14). This PR provides the skeleton structure for RISC OS support in Python 3.14.

Background

The RISC OS port of Python includes:

• Platform-specific modules (riscos, swi)
• Path handling adaptations (RISC OS uses . as directory separator and , as search path delimiter)
• Build system for RISC OS
• Platform-specific implementations for dynamic loading, sleep, and exception handling

Changes Required

Phase 1: Copy RISCOS Directory Structure

Copy the entire RISCOS/ directory from the riscos branch, containing:

• RISCOS/Makefile - Build system
• RISCOS/config.c - Module configuration
• RISCOS/pyconfig.h - Platform configuration
• RISCOS/getpath.c - Module search paths
• RISCOS/swimodule.c - SWI (Software Interrupt) interface
• RISCOS/ReleaseNotes - Documentation
• RISCOS/_Python3/ - Boot files and sprites
• RISCOS/_PythonUser/ - User files
• RISCOS/RiscPkg-38/ - Package metadata (rename to RiscPkg-314 and update version)

Note: The code in these files will need to be updated for Python 3.14 API changes in a follow-up, but copy them as-is first to establish the structure.

Phase 2: Add Conditional Compilation Blocks

Add #ifdef RISCOS blocks to the following files based on the riscos branch:

Include/osdefs.h

Add RISC OS path separators:

#ifdef RISCOS
#define DELIM L','
#define SEP L'.'
#endif

Include/cpython/pyerrors.h

Add RISCOSError exception structure:

#ifdef RISCOS
typedef struct {
    PyException_HEAD
    PyObject *errnum;
    PyObject *errmsg;
} PyRISCOSErrorObject;
#endif

Objects/exceptions.c

Add RISCOSError exception initialization:

#ifdef RISCOS
    PRE_INIT(RISCOSError);
#endif

Programs/python.c

Add riscosify control settings at the top:

#ifdef RISCOS
#include <unixlib/local.h>
int __riscosify_control =  __RISCOSIFY_NO_PROCESS |
                           __RISCOSIFY_NO_SUFFIX |
                           __RISCOSIFY_NO_REVERSE_SUFFIX;
#endif

Programs/_freeze_importlib.c

Add:

1. Include and riscosify control (same as python.c)
2. In the main() function, replace the _Py_fstat_noraise block with:

#ifdef RISCOS
    fseek(infile, 0, SEEK_END);
    text_size = ftell(infile);
    fseek(infile, 0, SEEK_SET);
#else
    if (_Py_fstat_noraise(fileno(infile), &stat)) {
        fprintf(stderr, "cannot fstat '%s'\n", inpath);
        goto error;
    }
    text_size = (size_t)stat.st_size;
#endif

Modules/getbuildinfo.c

In the Py_GetBuildInfo() function, replace the gitid initialization with:

#ifdef RISCOS
    const char *gitid = "riscos-1";
#else
    const char *gitid = _Py_gitidentifier();
    if (!(*gitid))
        gitid = "default";
#endif

Python/dynload_shlib.c

Add multiple changes:

1. After includes, add:

#ifdef RISCOS
#include <unixlib/local.h>
#endif

2. In the file extension table _PyImport_DynLoadFiletab:

const char *_PyImport_DynLoadFiletab[] = {
#if defined(RISCOS)
    "/so",
    "/" SOABI "/so",
#elif defined(__CYGWIN__)
    ".dll",
#else
    "." SOABI ".so",
#ifdef ALT_SOABI
    "." ALT_SOABI ".so",
#endif
    ".abi" PYTHON_ABI_STRING ".so",
    ".so",
#endif
    NULL,
};

3. In _PyImport_FindSharedFuncptr(), add RISCOS-specific path handling:

#ifndef RISCOS
    char pathbuf[260];

    if (strchr(pathname, '/') == NULL) {
        /* Prefix bare filename with "./" */
        PyOS_snprintf(pathbuf, sizeof(pathbuf), "./%-.255s", pathname);
        pathname = pathbuf;
    }
#endif

4. In the dlopen call section:

#ifdef RISCOS
    char* unixpath = __unixify(pathname, 0x0, 0, 0, -1);
    handle = dlopen(unixpath, dlopenflags);
    free(unixpath);
#else
    handle = dlopen(pathname, dlopenflags);
#endif

Modules/_ssl.c

In the _ssl_get_default_verify_paths_impl() function, add:

#ifdef RISCOS
    // The defaults from the X509_... calls are somewhat useless.
    ofile_env = Py_None; Py_INCREF(Py_None);
    ofile     = Py_None; Py_INCREF(Py_None);
    odir_env  = Py_None; Py_INCREF(Py_None);
    odir      = Py_None; Py_INCREF(Py_None);
#else
    CONVERT(X509_get_default_cert_file_env(), ofile_env);
    CONVERT(X509_get_default_cert_file(), ofile);
    CONVERT(X509_get_default_cert_dir_env(), odir_env);
    CONVERT(X509_get_default_cert_dir(), odir);
#endif

Modules/timemodule.c

In the pysleep() function, replace the select() call with:

#ifdef RISCOS
        unsigned int end = _swi(OS_ReadMonotonicTime, _RETURN(0)) +
                           (timeout.tv_sec * 100 + timeout.tv_usec / 10000);
       while ((unsigned)_swi(OS_ReadMonotonicTime, _RETURN(0)) < end) ;
#else
        err = select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout);
#endif

Python/initconfig.c

Add a RISC OS-specific version of config_wstr_to_int():

#...

</details>



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