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+LibMCPU HOST sysdeps
+====================
+
+This tree is the HOST-dependent adaptation layer for MCPU system-call wrappers.
+configure builds the ordered `sysnames` search list from the canonical HOST,
+architecture preconfigure fragments, the ABI/data model and Implies inheritance.
+cpu/Makefile.am uses that ordered list as the GNU make `vpath %.c` search path,
+so the first matching basename is the selected source.
+
+The search order is intentionally from the most specific implementation to the
+most generic implementation.  `cpu/sysdeps/generic` is always last.  A generic
+directory does not by itself make an otherwise unknown HOST supported.
+
+Starting with LibMCPU 0.3.25 raw HOST errno values must not escape this layer.
+The inherited `sys-errno.c` implementation provides `__cpu_errno_from_host()`;
+HOST syscall wrappers translate a real HOST failure into the stable MCPU errno
+namespace before returning to common CPU code.  Errors created by the MCPU ABI
+itself use `__MCPU_E*` constants directly and are not sent through the HOST
+translator.