From d089ef1003ce2064163ade40a67a1198fa55abfd Mon Sep 17 00:00:00 2001 From: Anton Korobeynikov Date: Sun, 3 May 2009 13:19:24 +0000 Subject: [PATCH] Add TODO list :) llvm-svn: 70768 --- llvm/lib/Target/MSP430/README.txt | 42 +++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 llvm/lib/Target/MSP430/README.txt diff --git a/llvm/lib/Target/MSP430/README.txt b/llvm/lib/Target/MSP430/README.txt new file mode 100644 index 000000000000..b14e93d84d6a --- /dev/null +++ b/llvm/lib/Target/MSP430/README.txt @@ -0,0 +1,42 @@ +//===---------------------------------------------------------------------===// +// MSP430 backend. +//===---------------------------------------------------------------------===// + +DISCLAIMER: Thid backend should be considered as highly experimental. I never +seen nor worked with this MCU, all information was gathered from datasheet +only. The original intention of making this backend was to write documentation +of form "How to write backend for dummies" :) Thes notes hopefully will be +available pretty soon. + +Some things are incomplete / not implemented yet (this list surely is not +complete as well): + +0. Implement asmprinting for variables :) + +1. Verify, how stuff is handling implicit zext with 8 bit operands (this might +be modelled currently in improper way - should we need to mark the superreg as +def for every 8 bit instruction?). + +2. Libcalls: multiplication, division, remainder. Note, that calling convention +for libcalls is incomptible with calling convention of libcalls of msp430-gcc +(these cannot be used though due to license restriction). + +3. Implement multiplication / division by constant (dag combiner hook?). + +4. Implement non-constant shifts. + +5. Implement varargs stuff. + +6. Verify and fix (if needed) how's stuff playing with i32 / i64. + +7. Implement floating point stuff (softfp?) + +8. Implement instruction encoding for (possible) direct code emission in the +future. + +9. Since almost all instructions set flags - implement brcond / select in better +way (currently they emit explicit comparison). + +10. Handle imm in comparisons in better way (see comment in MSP430InstrInfo.td) + +11. Implement hooks for better memory op folding, etc.