DOCUMENTATION:
-The internals of gas need documenting. (Actually, there is some documentation
-in doc/as.texinfo, but it's *way* out of date.)
+The internals of gas need documenting.
The documentation should also contain a "Trouble" section similar to gcc's
manual: real bugs, common problems, incompatibilities, etc.
another previous maintainer, unrelated to the code. (And with no names,
they're not so fun to read. :-)
+For sparc: "call 0" becomes "jmpl %g0,%l7", and similarly for absolute
+addresses in -4096...4095. (Solaris assembler does this. No
+relocation required, no absolute symbol needed.) For addresses
+outside the range, for COFF, keep generating an absolute symbol to use
+for relocs.
+
Get Steve to document H8/500 stuff (and others).
Improve test suite. Incorporate more reported net bugs, and non-confidential
PIC support.
+Torbjorn Granlund <tege@cygnus.com> writes, regarding alpha .align:
+
+ Please make sure the .align directive works as in digital's assembler.
+ They fill the space with a sequence of "bis $31,$31,$31;ldq_u $31,0($30)"
+ since these two instructions can dual-issue. Since .align is ued a lot by
+ gcc, it is an important optimization.
+
+Torbjorn Granlund <tege@cygnus.com> writes, regarding i386/i486/pentium:
+
+ In a new publication from Intel, "Optimization for Intel's 32 bit
+ Processors", they recommended code alignment on a 16 byte boundary if that
+ requires less than 8 bytes of fill instructions. The Pentium is not
+ affected by such alignment, the 386 wants alignment on a 4 byte boundary.
+ It is the 486 that is most helped by large alignment.
+
+ Recommended nop instructions:
+ 1 byte: 90 xchg %eax,%eax
+ 2 bytes: 8b c0 movl %eax,%eax
+ 3 bytes: 8d 76 00 leal 0(%esi),%esi
+ 4 bytes: 8d 74 26 00 leal 0(%esi),%esi
+ 5 bytes: 8b c0 8d 76 00 movl %eax,%eax; leal 0(%esi),%esi
+ 6 bytes: 8d b6 00 00 00 00 leal 0(%esi),%esi
+ 7 bytes: 8d b4 26 00 00 00 00 leal 0(%esi),%esi
+
+ Note that `leal 0(%esi),%esi' has a few different encodings...
+
+ There are faster instructions for certain lengths, that are not true nops.
+ If you can determine that a register and the condition code is dead (by
+ scanning forwards for a register that is written before it is read, and
+ similar for cc) you can use a `incl reg' for a 3 times faster 1 cycle nop...
+
(From old "NOTES" file to-do list, not really reviewed:)
fix relocation types for i860, perhaps by adding a ref pointer to fixS?