Mercurial > hg > CbC > CbC_llvm
comparison lib/Target/MSP430/README.txt @ 0:95c75e76d11b LLVM3.4
LLVM 3.4
| author | Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Thu, 12 Dec 2013 13:56:28 +0900 |
| parents | |
| children | 60c9769439b8 |
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| -1:000000000000 | 0:95c75e76d11b |
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| 1 //===---------------------------------------------------------------------===// | |
| 2 // MSP430 backend. | |
| 3 //===---------------------------------------------------------------------===// | |
| 4 | |
| 5 DISCLAIMER: Thid backend should be considered as highly experimental. I never | |
| 6 seen nor worked with this MCU, all information was gathered from datasheet | |
| 7 only. The original intention of making this backend was to write documentation | |
| 8 of form "How to write backend for dummies" :) Thes notes hopefully will be | |
| 9 available pretty soon. | |
| 10 | |
| 11 Some things are incomplete / not implemented yet (this list surely is not | |
| 12 complete as well): | |
| 13 | |
| 14 1. Verify, how stuff is handling implicit zext with 8 bit operands (this might | |
| 15 be modelled currently in improper way - should we need to mark the superreg as | |
| 16 def for every 8 bit instruction?). | |
| 17 | |
| 18 2. Libcalls: multiplication, division, remainder. Note, that calling convention | |
| 19 for libcalls is incomptible with calling convention of libcalls of msp430-gcc | |
| 20 (these cannot be used though due to license restriction). | |
| 21 | |
| 22 3. Implement multiplication / division by constant (dag combiner hook?). | |
| 23 | |
| 24 4. Implement non-constant shifts. | |
| 25 | |
| 26 5. Implement varargs stuff. | |
| 27 | |
| 28 6. Verify and fix (if needed) how's stuff playing with i32 / i64. | |
| 29 | |
| 30 7. Implement floating point stuff (softfp?) | |
| 31 | |
| 32 8. Implement instruction encoding for (possible) direct code emission in the | |
| 33 future. | |
| 34 | |
| 35 9. Since almost all instructions set flags - implement brcond / select in better | |
| 36 way (currently they emit explicit comparison). | |
| 37 | |
| 38 10. Handle imm in comparisons in better way (see comment in MSP430InstrInfo.td) | |
| 39 | |
| 40 11. Implement hooks for better memory op folding, etc. |