explorer | Block explorer showcasing the BlockCypher APIs | Frontend Framework library
kandi X-RAY | explorer Summary
kandi X-RAY | explorer Summary
Block explorer showcasing the BlockCypher APIs.
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
- Setup the address forwarding form
- Send a message and log it
- Sends email forwarding welcome email
- Returns the full username
- View of the block view
- Given a wallet name and a currency return its address
- Creates address subscriptions
- Sends a confirmation email
- Unsubscribe subscription
- View address details
- Subscribe to a given address
- View for a transaction
- View for wallet overview
- View block height
- Signup a user
- Reset a user s password
- View to confirm a subscription
- Unsubscribe from notification
- View function that handles a password reset
- Get the confidence of a transaction
- Unsubscribe an address subscription
- Creates a superuser
- Create a webhook instance
- Clean search string
- Retry the webhook
- Return the dashboard
explorer Key Features
explorer Examples and Code Snippets
Community Discussions
Trending Discussions on explorer
QUESTION
When I launch in VSCode dlv dap debug, I get this message:
...ANSWER
Answered 2021-Aug-13 at 15:50You might have some luck switching the delveConfig to use legacy mode:
QUESTION
While testing things around Compiler Explorer, I tried out the following overflow-free function for calculating average of 2 unsigned 32-bit integer:
...ANSWER
Answered 2022-Mar-08 at 10:00Clang does the same thing. Probably for compiler-construction and CPU architecture reasons:
Disentangling that logic into just a swap may allow better optimization in some cases; definitely something it makes sense for a compiler to do early so it can follow values through the swap.
Xor-swap is total garbage for swapping registers, the only advantage being that it doesn't need a temporary. But
xchg reg,reg
already does that better.
I'm not surprised that GCC's optimizer recognizes the xor-swap pattern and disentangles it to follow the original values. In general, this makes constant-propagation and value-range optimizations possible through swaps, especially for cases where the swap wasn't conditional on the values of the vars being swapped. This pattern-recognition probably happens soon after transforming the program logic to GIMPLE (SSA) representation, so at that point it will forget that the original source ever used an xor swap, and not think about emitting asm that way.
Hopefully sometimes that lets it then optimize down to only a single mov
, or two mov
s, depending on register allocation for the surrounding code (e.g. if one of the vars can move to a new register, instead of having to end up back in the original locations). And whether both variables are actually used later, or only one. Or if it can fully disentangle an unconditional swap, maybe no mov
instructions.
But worst case, three mov
instructions needing a temporary register is still better, unless it's running out of registers. I'd guess GCC is not smart enough to use xchg reg,reg
instead of spilling something else or saving/restoring another tmp reg, so there might be corner cases where this optimization actually hurts.
(Apparently GCC -Os
does have a peephole optimization to use xchg reg,reg
instead of 3x mov: PR 92549 was fixed for GCC10. It looks for that quite late, during RTL -> assembly. And yes, it works here: turning your xor-swap into an xchg: https://godbolt.org/z/zs969xh47)
with no memory reads, and the same number of instructions, I don't see any bad impacts and feels odd that it be changed. Clearly there is something I did not think through though, but what is it?
Instruction count is only a rough proxy for one of three things that are relevant for perf analysis: front-end uops, latency, and back-end execution ports. (And machine-code size in bytes: x86 machine-code instructions are variable-length.)
It's the same size in machine-code bytes, and same number of front-end uops, but the critical-path latency is worse: 3 cycles from input a
to output a
for xor-swap, and 2 from input b
to output a
, for example.
MOV-swap has at worst 1-cycle and 2-cycle latencies from inputs to outputs, or less with mov-elimination. (Which can also avoid using back-end execution ports, especially relevant for CPUs like IvyBridge and Tiger Lake with a front-end wider than the number of integer ALU ports. And Ice Lake, except Intel disabled mov-elimination on it as an erratum workaround; not sure if it's re-enabled for Tiger Lake or not.)
Also related:
- Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? - and those 3 uops can't benefit from mov-elimination. But on modern AMD
xchg reg,reg
is only 2 uops.
GCC's real missed optimization here (even with -O3
) is that tail-duplication results in about the same static code size, just a couple extra bytes since these are mostly 2-byte instructions. The big win is that the a
path then becomes the same length as the other, instead of twice as long to first do a swap and then run the same 3 uops for averaging.
update: GCC will do this for you with -ftracer
(https://godbolt.org/z/es7a3bEPv), optimizing away the swap. (That's only enabled manually or as part of -fprofile-use
, not at -O3
, so it's probably not a good idea to use all the time without PGO, potentially bloating machine code in cold functions / code-paths.)
Doing it manually in the source (Godbolt):
QUESTION
Discussion about this was started under this answer for quite simple question.
ProblemThis simple code has unexpected overload resolution of constructor for std::basic_string
:
ANSWER
Answered 2022-Jan-05 at 12:05Maybe I'm wrong, but it seems that last part:
QUESTION
I feel like there is probably a better way to do this in tidyverse
than a for-loop
. Start with a standard tibble/dataframe, and make a list where the name of the list elements are the unique values of one column (group_by
?) and the list elements are all the values of another column.
ANSWER
Answered 2022-Jan-13 at 17:16We can use split
QUESTION
The following code
...ANSWER
Answered 2022-Jan-11 at 09:42The bug has been fixed and the example now compiles.
QUESTION
I have a TypeScript project (https://github.com/jmaister/excellentexport) and it is working fine.
After adding the dependabot process, it suggests upgrading typescript:
...ANSWER
Answered 2021-Oct-08 at 06:22I ran into the exact same issue recently, and the solution I arrived at was to extend the Navigator
interface in the global
namespace so it still includes msSaveBlob
, based on how msSaveBlob
is documented by TypeScript here: MSFileSaver
Here is the code I used:
QUESTION
Given that the C++ standard library doesn't (currently) provide constexpr versions of the cmath functions, consider the program below.
...ANSWER
Answered 2021-Dec-29 at 18:23As noted, the C++ standard library doesn't currently support constexpr
evaluation of cmath functions. However, that doesn't prevent individual implementations from having non-standard code. GCC has a nonconforming extension that allows constexpr
evaluation.
QUESTION
Consider the following:
...ANSWER
Answered 2021-Dec-30 at 08:54If you look closely at the specification of ranges::size
in [range.prim.size], except when the type of R
is the primitive array type, ranges::size
obtains the size of r
by calling the size()
member function or passing it into a free function.
And since the parameter type of transform()
function is reference, ranges::size(r)
cannot be used as a constant expression in the function body, this means we can only get the size of r
through the type of R
, not the object of R
.
However, there are not many standard range types that contain size information, such as primitive arrays, std::array
, std::span
, and some simple range adaptors. So we can define a function to detect whether R
is of these types, and extract the size from its type in a corresponding way.
QUESTION
This follows as a result of experimenting on Compiler Explorer as to ascertain the compiler's (rustc's) behaviour when it comes to the log2()
/leading_zeros()
and similar functions. I came across this result with seems exceedingly both bizarre and concerning:
Code:
...ANSWER
Answered 2021-Dec-26 at 01:56Old x86-64 CPUs don't support lzcnt
, so rustc/llvm won't emit it by default. (They would execute it as bsr
but the behavior is not identical.)
Use -C target-feature=+lzcnt
to enable it. Try.
More generally, you may wish to use -C target-cpu=XXX
to enable all the features of a specific CPU model. Use rustc --print target-cpus
for a list.
In particular, -C target-cpu=native
will generate code for the CPU that rustc itself is running on, e.g. if you will run the code on the same machine where you are compiling it.
QUESTION
Update: relevant GCC bug report: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103798
I tested the following code:
...ANSWER
Answered 2021-Dec-21 at 11:08libstdc++'s std::string_view::find_first_of
looks something like:
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install explorer
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page