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@@ -21,3 +21,106 @@ bootstrapping, and Linux distributions built on musl can be found on
the project website:
http://www.musl-libc.org/
+
+Quick Installation Guide for musl libc
+======================================
+
+There are many different ways to install musl depending on your usage
+case. This document covers only the build and installation of musl by
+itself, which is useful for upgrading an existing musl-based system or
+compiler toolchain, or for using the provided musl-gcc wrapper with an
+existing non-musl-based compiler.
+
+Building complete native or cross-compiler toolchains is outside the
+scope of this INSTALL file. More information can be found on the musl
+website and community wiki.
+
+
+Build Prerequisites
+-------------------
+
+The only build-time prerequisites for musl are GNU Make and a
+freestanding C99 compiler toolchain targeting the desired instruction
+set architecture and ABI, with support for a minimal subset of "GNU C"
+extensions consisting mainly of gcc-style inline assembly, weak
+aliases, hidden visibility, and stand-alone assembly source files.
+
+GCC, LLVM/clang, Firm/cparser, and PCC have all successfully built
+musl, but GCC is the most widely used/tested. Recent compiler (and
+binutils) versions should be used if possible since some older
+versions have bugs which affect musl.
+
+The system used to build musl does not need to be Linux-based, nor do
+the Linux kernel headers need to be available.
+
+
+
+Supported Targets
+-----------------
+
+musl can be built for the following CPU instruction set architecture
+and ABI combinations:
+
+* i386
+ * Minimum CPU model is actually 80486 unless kernel emulation of
+ the `cmpxchg` instruction is added
+
+* x86_64
+ * ILP32 ABI (x32) is available as a separate arch but is still
+ experimental
+
+* ARM
+ * EABI, standard or hard-float VFP variant
+ * Little-endian default; big-endian variants also supported
+ * Compiler toolchains only support armv4t and later
+
+* AArch64
+ * Little-endian default; big-endian variants also supported
+
+* MIPS
+ * ABI is o32, fp32/fpxx (except on r6 which is fp64)
+ * Big-endian default; little-endian variants also supported
+ * Default ABI variant uses FPU registers; alternate soft-float ABI
+ that does not use FPU registers or instructions is available
+ * MIPS2 or later, or kernel emulation of ll/sc (standard in Linux)
+ is required
+ * MIPS32r6, an incompatible ISA, is supported as a variant "mipsr6"
+
+* MIPS64
+ * ABI is n64 (LP64) or n32 (ILP32)
+ * Big-endian default; little-endian variants also supported
+ * Default ABI variant uses FPU registers; alternate soft-float ABI
+ that does not use FPU registers or instructions is available
+
+* PowerPC
+ * Compiler toolchain must provide 64-bit long double, not IBM
+ double-double or IEEE quad
+ * For dynamic linking, compiler toolchain must be configured for
+ "secure PLT" variant
+
+* PowerPC64
+ * Both little and big endian variants are supported
+ * Compiler toolchain must provide 64-bit long double, not IBM
+ double-double or IEEE quad
+ * Compiler toolchain must use the new (ELFv2) ABI regardless of
+ whether it is for little or big endian
+
+* S390X (64-bit S390)
+
+* SuperH (SH)
+ * Standard ELF ABI or FDPIC ABI (shared-text without MMU)
+ * Little-endian by default; big-endian variant also supported
+ * Full FPU ABI or soft-float ABI is supported, but the
+ single-precision-only FPU ABI is not
+
+* Microblaze
+ * Big-endian default; little-endian variants also supported
+ * Soft-float
+ * Requires support for lwx/swx instructions
+
+* OpenRISC 1000 (or1k)
+
+* RISC-V 64
+ * Little endian
+ * Hard, soft, and hard-single/soft-double floating point ABIs
+ * Standard ELF; no shared-text NOMMU support