README: add Contributing and Progress sections

Author: Jorge Aparicio

README.md

@@ -10,6 +10,312 @@ See [rust-lang/rust#35437][0].
 
 [0]: https://github.com/rust-lang/rust/issues/35437
 
+## Contributing
+
+1. Pick one or more intrinsics from the [pending list][/#progress].
+2. Fork this repository
+3. Port the intrinsic(s) and their corresponding [unit tests][1] from their [C implementation][2] to
+   Rust.
+4. Send a Pull Request (PR)
+5. Once the PR passes our extensive [testing infrastructure][3], we'll merge it!
+6. Celebrate :tada:
+
+[1]: https://github.com/rust-lang/compiler-rt/tree/8598065bd965d9713bfafb6c1e766d63a7b17b89/test/builtins/Unit
+[2]: https://github.com/rust-lang/compiler-rt/tree/8598065bd965d9713bfafb6c1e766d63a7b17b89/lib/builtins
+[3]: https://travis-ci.org/japaric/rustc-builtins
+
+## Progress
+
+The intrinsics that involve quadruple precision floating point numbers ("`f128`") has been crossed
+off because Rust doesn't support them.
+
+- [ ] absvdi2.c
+- [ ] absvsi2.c
+- [ ] absvti2.c
+- [ ] adddf3.c
+- [ ] addsf3.c
+- [ ] addtf3.c
+- [ ] addvdi3.c
+- [ ] addvsi3.c
+- [ ] addvti3.c
+- [ ] apple_versioning.c
+- [ ] arm/adddf3vfp.S
+- [ ] arm/addsf3vfp.S
+- [ ] arm/aeabi_cdcmp.S
+- [ ] arm/aeabi_cdcmpeq_check_nan.c
+- [ ] arm/aeabi_cfcmp.S
+- [ ] arm/aeabi_cfcmpeq_check_nan.c
+- [ ] arm/aeabi_dcmp.S
+- [ ] arm/aeabi_div0.c
+- [ ] arm/aeabi_drsub.c
+- [ ] arm/aeabi_fcmp.S
+- [ ] arm/aeabi_frsub.c
+- [ ] arm/aeabi_idivmod.S
+- [ ] arm/aeabi_ldivmod.S
+- [ ] arm/aeabi_uidivmod.S
+- [ ] arm/aeabi_uldivmod.S
+- [ ] arm/bswapdi2.S
+- [ ] arm/bswapsi2.S
+- [ ] arm/clzdi2.S
+- [ ] arm/clzsi2.S
+- [ ] arm/comparesf2.S
+- [ ] arm/divdf3vfp.S
+- [ ] arm/divmodsi4.S
+- [ ] arm/divsf3vfp.S
+- [ ] arm/divsi3.S
+- [ ] arm/eqdf2vfp.S
+- [ ] arm/eqsf2vfp.S
+- [ ] arm/extendsfdf2vfp.S
+- [ ] arm/fixdfsivfp.S
+- [ ] arm/fixsfsivfp.S
+- [ ] arm/fixunsdfsivfp.S
+- [ ] arm/fixunssfsivfp.S
+- [ ] arm/floatsidfvfp.S
+- [ ] arm/floatsisfvfp.S
+- [ ] arm/floatunssidfvfp.S
+- [ ] arm/floatunssisfvfp.S
+- [ ] arm/gedf2vfp.S
+- [ ] arm/gesf2vfp.S
+- [ ] arm/gtdf2vfp.S
+- [ ] arm/gtsf2vfp.S
+- [ ] arm/ledf2vfp.S
+- [ ] arm/lesf2vfp.S
+- [ ] arm/ltdf2vfp.S
+- [ ] arm/ltsf2vfp.S
+- [ ] arm/modsi3.S
+- [ ] arm/muldf3vfp.S
+- [ ] arm/mulsf3vfp.S
+- [ ] arm/nedf2vfp.S
+- [ ] arm/negdf2vfp.S
+- [ ] arm/negsf2vfp.S
+- [ ] arm/nesf2vfp.S
+- [ ] arm/restore_vfp_d8_d15_regs.S
+- [ ] arm/save_vfp_d8_d15_regs.S
+- [ ] arm/softfloat-alias.list
+- [ ] arm/subdf3vfp.S
+- [ ] arm/subsf3vfp.S
+- [ ] arm/switch16.S
+- [ ] arm/switch32.S
+- [ ] arm/switch8.S
+- [ ] arm/switchu8.S
+- [ ] arm/sync_fetch_and_add_4.S
+- [ ] arm/sync_fetch_and_add_8.S
+- [ ] arm/sync_fetch_and_and_4.S
+- [ ] arm/sync_fetch_and_and_8.S
+- [ ] arm/sync_fetch_and_max_4.S
+- [ ] arm/sync_fetch_and_max_8.S
+- [ ] arm/sync_fetch_and_min_4.S
+- [ ] arm/sync_fetch_and_min_8.S
+- [ ] arm/sync_fetch_and_nand_4.S
+- [ ] arm/sync_fetch_and_nand_8.S
+- [ ] arm/sync_fetch_and_or_4.S
+- [ ] arm/sync_fetch_and_or_8.S
+- [ ] arm/sync_fetch_and_sub_4.S
+- [ ] arm/sync_fetch_and_sub_8.S
+- [ ] arm/sync_fetch_and_umax_4.S
+- [ ] arm/sync_fetch_and_umax_8.S
+- [ ] arm/sync_fetch_and_umin_4.S
+- [ ] arm/sync_fetch_and_umin_8.S
+- [ ] arm/sync_fetch_and_xor_4.S
+- [ ] arm/sync_fetch_and_xor_8.S
+- [ ] arm/sync_synchronize.S
+- [ ] arm/truncdfsf2vfp.S
+- [ ] arm/udivmodsi4.S
+- [ ] arm/udivsi3.S
+- [ ] arm/umodsi3.S
+- [ ] arm/unorddf2vfp.S
+- [ ] arm/unordsf2vfp.S
+- [ ] ashldi3.c
+- [ ] ashlti3.c
+- [ ] ashrdi3.c
+- [ ] ashrti3.c
+- [ ] atomic.c
+- [ ] atomic_flag_clear.c
+- [ ] atomic_flag_clear_explicit.c
+- [ ] atomic_flag_test_and_set.c
+- [ ] atomic_flag_test_and_set_explicit.c
+- [ ] atomic_signal_fence.c
+- [ ] atomic_thread_fence.c
+- [ ] clear_cache.c
+- [ ] clzdi2.c
+- [ ] clzsi2.c
+- [ ] clzti2.c
+- [ ] cmpdi2.c
+- [ ] cmpti2.c
+- [ ] comparedf2.c
+- [ ] comparesf2.c
+- [ ] comparetf2.c
+- [ ] cpu_model.c
+- [ ] ctzdi2.c
+- [ ] ctzsi2.c
+- [ ] ctzti2.c
+- [ ] divdc3.c
+- [ ] divdf3.c
+- [ ] divdi3.c
+- [ ] divmoddi4.c
+- [ ] divmodsi4.c
+- [ ] divsc3.c
+- [ ] divsf3.c
+- [ ] divsi3.c
+- [ ] divtc3.c
+- [ ] divtf3.c
+- [ ] divti3.c
+- [ ] divxc3.c
+- [ ] emutls.c
+- [ ] enable_execute_stack.c
+- [ ] eprintf.c
+- [ ] extenddftf2.c
+- [ ] extendhfsf2.c
+- [ ] extendsfdf2.c
+- [ ] extendsftf2.c
+- [ ] ffsdi2.c
+- [ ] ffsti2.c
+- [ ] fixdfdi.c
+- [ ] fixdfsi.c
+- [ ] fixdfti.c
+- [ ] fixsfdi.c
+- [ ] fixsfsi.c
+- [ ] fixsfti.c
+- [ ] fixtfdi.c
+- [ ] fixtfsi.c
+- [ ] fixtfti.c
+- [ ] fixunsdfdi.c
+- [ ] fixunsdfsi.c
+- [ ] fixunsdfti.c
+- [ ] fixunssfdi.c
+- [ ] fixunssfsi.c
+- [ ] fixunssfti.c
+- [ ] fixunstfdi.c
+- [ ] fixunstfsi.c
+- [ ] fixunstfti.c
+- [ ] floatdidf.c
+- [ ] floatdisf.c
+- [ ] floatditf.c
+- [ ] floatsidf.c
+- [ ] floatsisf.c
+- [ ] floatsitf.c
+- [ ] floattidf.c
+- [ ] floattisf.c
+- [ ] floatundidf.c
+- [ ] floatundisf.c
+- [ ] floatunditf.c
+- [ ] floatunsidf.c
+- [ ] floatunsisf.c
+- [ ] floatunsitf.c
+- [ ] floatuntidf.c
+- [ ] floatuntisf.c
+- [ ] gcc_personality_v0.c
+- [ ] i386/ashldi3.S
+- [ ] i386/ashrdi3.S
+- [ ] i386/chkstk.S
+- [ ] i386/chkstk2.S
+- [ ] i386/divdi3.S
+- [ ] i386/floatdidf.S
+- [ ] i386/floatdisf.S
+- [ ] i386/floatundidf.S
+- [ ] i386/floatundisf.S
+- [ ] i386/lshrdi3.S
+- [ ] i386/moddi3.S
+- [ ] i386/muldi3.S
+- [ ] i386/udivdi3.S
+- [ ] i386/umoddi3.S
+- [ ] int_util.c
+- [ ] lshrdi3.c
+- [ ] lshrti3.c
+- [ ] moddi3.c
+- [ ] modsi3.c
+- [ ] modti3.c
+- [ ] muldc3.c
+- [ ] muldf3.c
+- [ ] muldi3.c
+- [ ] mulodi4.c
+- [ ] mulosi4.c
+- [ ] muloti4.c
+- [ ] mulsc3.c
+- [ ] mulsf3.c
+- [ ] multc3.c
+- [ ] multf3.c
+- [ ] multi3.c
+- [ ] mulvdi3.c
+- [ ] mulvsi3.c
+- [ ] mulvti3.c
+- [ ] mulxc3.c
+- [ ] negdf2.c
+- [ ] negdi2.c
+- [ ] negsf2.c
+- [ ] negti2.c
+- [ ] negvdi2.c
+- [ ] negvsi2.c
+- [ ] negvti2.c
+- [ ] paritydi2.c
+- [ ] paritysi2.c
+- [ ] parityti2.c
+- [ ] popcountdi2.c
+- [ ] popcountsi2.c
+- [ ] popcountti2.c
+- [ ] powidf2.c
+- [ ] powisf2.c
+- [ ] powitf2.c
+- [ ] ppc/divtc3.c
+- [ ] ppc/fixtfdi.c
+- [ ] ppc/fixunstfdi.c
+- [ ] ppc/floatditf.c
+- [ ] ppc/floatunditf.c
+- [ ] ppc/gcc_qadd.c
+- [ ] ppc/gcc_qdiv.c
+- [ ] ppc/gcc_qmul.c
+- [ ] ppc/gcc_qsub.c
+- [ ] ppc/multc3.c
+- [ ] ppc/restFP.S
+- [ ] ppc/saveFP.S
+- [ ] subdf3.c
+- [ ] subsf3.c
+- [ ] subtf3.c
+- [ ] subvdi3.c
+- [ ] subvsi3.c
+- [ ] subvti3.c
+- [ ] trampoline_setup.c
+- [ ] truncdfhf2.c
+- [ ] truncdfsf2.c
+- [ ] truncsfhf2.c
+- [ ] trunctfdf2.c
+- [ ] trunctfsf2.c
+- [ ] ucmpdi2.c
+- [ ] ucmpti2.c
+- [ ] udivdi3.c
+- [ ] udivmoddi4.c
+- [ ] udivmodsi4.c
+- [ ] udivmodti4.c
+- [ ] udivsi3.c
+- [ ] udivti3.c
+- [ ] umoddi3.c
+- [ ] umodsi3.c
+- [ ] umodti3.c
+- [ ] x86_64/chkstk.S
+- [ ] x86_64/chkstk2.S
+- [ ] x86_64/floatundidf.S
+- [ ] x86_64/floatundisf.S
+- [x] arm/aeabi_memcmp.S
+- [x] arm/aeabi_memcpy.S
+- [x] arm/aeabi_memmove.S
+- [x] arm/aeabi_memset.S
+- [x] x86_64/floatdidf.c
+- [x] x86_64/floatdisf.c
+- ~~fixunsxfdi.c~~
+- ~~fixunsxfsi.c~~
+- ~~fixunsxfti.c~~
+- ~~fixxfdi.c~~
+- ~~fixxfti.c~~
+- ~~floatdixf.c~~
+- ~~floattixf.c~~
+- ~~floatundixf.c~~
+- ~~floatuntixf.c~~
+- ~~i386/floatdixf.S~~
+- ~~i386/floatundixf.S~~
+- ~~powixf2.c~~
+- ~~x86_64/floatdixf.c~~
+- ~~x86_64/floatundixf.S~~
+
 ## License
 
 Licensed under either of