All three cases of clearfat were wrong on power64x.

The cases that handle 1032 bytes and up and 32 bytes and up
both use MOVDU (one directly generated in a loop and the other
via duffzero), which leaves the pointer register pointing at
the *last written* address.  The generated code was not
accounting for this, so the byte fill loop was re-zeroing the
last zeroed dword, rather than the bytes following the last
zeroed dword.  Fix this by simply adding an additional 8 byte
offset to the byte zeroing loop.

The case that handled under 32 bytes was also wrong.  It
didn't update the pointer register at all, so the byte zeroing
loop was simply re-zeroing the beginning of region.  Again,
the fix is to add an offset to the byte zeroing loop to
account for this.

LGTM=dave, bradfitz
R=rsc, dave, bradfitz
CC=golang-codereviews
https://golang.org/cl/168870043

Apparently I had already moved on to fixing another problem
when I submitted CL 169790043.

LGTM=dave
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/165210043

No real problems found.  Just lots of argument names that
didn't quite match up.

LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/169790043

LGTM=bradfitz
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/162500043

This adds a test to runtime·check to ensure CAS of large
unsigned 32-bit numbers does not accidentally sign-extend its
arguments.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/162490044

Previously, the power64x runtime assembly was sloppy about
using sign-extending versus zero-extending moves of arguments
and return values.  I think all of the cases that actually
mattered have been fixed in recent CLs; this CL fixes up the
few remaining mismatches.

LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/162480043

Still passes on amd64.

LGTM=austin
R=austin
CC=golang-codereviews
https://golang.org/cl/165110043

Stupid mistake in previous CL.

TBR=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/166880043

TBR=iant
CC=golang-codereviews
https://golang.org/cl/164180043

TBR=austin
CC=golang-codereviews
https://golang.org/cl/167820043

TBR=austin
CC=golang-codereviews
https://golang.org/cl/162420043

Fixes #8803.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/169720043

Fixes #9006.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/167800043

It now echoes what strconv.FormatFloat says.

Fixes #9012.

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/169730043

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/160660046

Fixes #8861.
Fixes #8911.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/165780043

Fixes #8588.

LGTM=austin
R=austin
CC=golang-codereviews, khr
https://golang.org/cl/159700044

goprintf is a printf-like print for Go.
It is used in the code generated by 'defer print(...)' and 'go print(...)'.

Normally print(1, 2, 3) turns into

        printint(1)
        printint(2)
        printint(3)

but defer and go need a single function call to give the runtime;
they give the runtime something like goprintf("%d%d%d", 1, 2, 3).

Variadic functions like goprintf cannot be described in the new
type information world, so we have to replace it.

Replace with a custom function, so that defer print(1, 2, 3) turns
into

        defer func(a1, a2, a3 int) {
                print(a1, a2, a3)
        }(1, 2, 3)

(and then the print becomes three different printints as usual).

Fixes #8614.

LGTM=austin
R=austin
CC=golang-codereviews, r
https://golang.org/cl/159700043

I removed support for jumping between functions years ago,
as part of doing the instruction layout for each function separately.

Given that, it makes sense to treat labels as function-scoped.
This lets each function have its own 'loop' label, for example.

Makes the assembly much cleaner and removes the last
reason anyone would reach for the 123(PC) form instead.

Note that this is on the dev.power64 branch, but it changes all
the assemblers. The change will ship in Go 1.5 (perhaps after
being ported into the new assembler).

Came up as part of CL 167730043.

LGTM=r
R=r
CC=austin, dave, golang-codereviews, minux
https://golang.org/cl/159670043

In CL 160670043 the write function was changed
so a zero-length write is now allowed. This leads
the ExampleWriter_Init test to fail.

The reason is that Plan 9 preserves message
boundaries, while the os library expects systems
that don't preserve them. We have to ignore
zero-length writes so they will never turn into EOF.

This issue was previously discussed in CL 7406046.

LGTM=bradfitz
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/163510043

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/166850043

Power64 servers do not currently support sub-word size atomic
memory access, so atomicor8 uses word size atomic access.
However, previously atomicor8 made no attempt to align this
access, resulting in errors.  Fix this by aligning the pointer
to a word boundary and shifting the value appropriately.
Since atomicor8 is used in GC, add a test to runtime·check to
make sure this doesn't break in the future.

This also fixes an incorrect branch label, an incorrectly
sized argument move, and adds argument names to help go vet.

LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/165820043

Also a few other minor changes.

Fixes #8712.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/164150043

TBR=crawshaw
CC=golang-codereviews
https://golang.org/cl/162390043

LGTM=rsc, aram, minux
R=golang-codereviews, aram, minux, rsc
CC=golang-codereviews
https://golang.org/cl/162370045

The "to" field was the penultimate argument to outgcode,
instead of the last argument, which swapped the third and
fourth operands.  The argument order was correct in a.y, so
just swap the meaning of the arguments in outgcode.  This
hadn't come up because we hadn't used these more obscure
operations in any hand-written assembly until now.

LGTM=rsc, dave
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/160690043

Fixes #9007.

LGTM=iant, r
R=r, iant
CC=golang-codereviews
https://golang.org/cl/160670043

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/165800043

Fixes #8787.

LGTM=rsc
R=rsc, dvyukov
CC=golang-codereviews
https://golang.org/cl/153670043

No easy way to test (would have to actually trigger some routing
events from kernel) but the code is clearly wrong as written.
If the header says there is a submessage, we need to at least
skip over its bytes, not just continue to the next iteration.

Fixes #8203.

LGTM=r
R=r
CC=golang-codereviews, mikioh.mikioh, p
https://golang.org/cl/164140044

get -u now checks that remote repo paths match the
ones predicted by the import paths: if you are get -u'ing
rsc.io/pdf, it has to be checked out from the right location.
This is important in case the rsc.io/pdf redirect changes.

In some cases, people have good reasons to use
non-standard remote repos. Add -f flag to allow that.
The f can stand for force or fork, as you see fit.

Fixes #8850.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/164120043

The wrapper code was being emitted before the stack
reservation, rather than after.

LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/161540043

Just to confirm the fix, by typing the follwing:
go test -run=TestLookupIPDeadline -dnsflood or
go test -run=TestLookupIPDeadline -dnsflood -tags netgo

Update #8602

LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/166740043

still need to do internal and import comments

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/160600043

LGTM=adg, rsc
R=golang-codereviews, adg, bradfitz, dave, rsc
CC=golang-codereviews
https://golang.org/cl/164090044

This leaked into the CL I submitted for Minux,
because I was testing it.

TBR=adg
CC=golang-codereviews
https://golang.org/cl/159600044

NaCl creates /tmp. This lets the zip file populate it.

LGTM=adg
R=adg
CC=golang-codereviews
https://golang.org/cl/159600043

Revived from CL 15690048.

Fixes #5356.

LGTM=rsc
R=adg, dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/101400043

cas64 was jumping to the wrong offset.

LGTM=minux, rsc
R=rsc, austin, minux
CC=golang-codereviews
https://golang.org/cl/158710043

Add a short introductory section saying what most Go
programmers really need to know, which is that you
shouldn't have to read this document to understand
the behavior of your program.

LGTM=bradfitz, adg, tracey.brendan, iant, rsc, dsymonds
R=golang-codereviews, bradfitz, tracey.brendan, adg, iant, rsc, dsymonds
CC=golang-codereviews
https://golang.org/cl/158500043