how can we run 4 IPC with only two 512bits SIMD ALUs? that what's register renaming gives you. there's 118 G instructions, but only 81 G μops hits the backend
January 9, 2026 at 11:57 AM
how can we run 4 IPC with only two 512bits SIMD ALUs? that what's register renaming gives you. there's 118 G instructions, but only 81 G μops hits the backend
wow, this chunk of full-width avx512 code is running at 4.2 instructions per cycle near the peak single core boost frequency
January 9, 2026 at 11:56 AM
wow, this chunk of full-width avx512 code is running at 4.2 instructions per cycle near the peak single core boost frequency
the only interesting thing in this article is that the go compiler still cannot do even the most trivial if-conversion
skoredin.pro/blog/golang/...
meanwhile in the world of if-conversion/predication: research arxiv.org/pdf/2512.22390
skoredin.pro/blog/golang/...
meanwhile in the world of if-conversion/predication: research arxiv.org/pdf/2512.22390
January 8, 2026 at 3:24 PM
the only interesting thing in this article is that the go compiler still cannot do even the most trivial if-conversion
skoredin.pro/blog/golang/...
meanwhile in the world of if-conversion/predication: research arxiv.org/pdf/2512.22390
skoredin.pro/blog/golang/...
meanwhile in the world of if-conversion/predication: research arxiv.org/pdf/2512.22390
avx512 is absolutely fantastic
bit blending `(a & m) | (b & ~m)` is `vpxor, vpand, vpxor` sequence on avx2 but a single `vpternlogq` instruction on avx512
and on icelake/tigerlake cpus you can do two full width ternlogs every cycle
bit blending `(a & m) | (b & ~m)` is `vpxor, vpand, vpxor` sequence on avx2 but a single `vpternlogq` instruction on avx512
and on icelake/tigerlake cpus you can do two full width ternlogs every cycle
January 7, 2026 at 2:03 PM
avx512 is absolutely fantastic
bit blending `(a & m) | (b & ~m)` is `vpxor, vpand, vpxor` sequence on avx2 but a single `vpternlogq` instruction on avx512
and on icelake/tigerlake cpus you can do two full width ternlogs every cycle
bit blending `(a & m) | (b & ~m)` is `vpxor, vpand, vpxor` sequence on avx2 but a single `vpternlogq` instruction on avx512
and on icelake/tigerlake cpus you can do two full width ternlogs every cycle
každý den se nějaký čůrák za volantem najde.
margaras.k47.cz/@k47/statuse...
margaras.k47.cz/@k47/statuse...
October 15, 2025 at 4:34 PM
každý den se nějaký čůrák za volantem najde.
margaras.k47.cz/@k47/statuse...
margaras.k47.cz/@k47/statuse...
fun fact: PHP manages memory using reference counting, but xml extensions for some reason implement their own reference counting on top of general reference counting.
github.com/php/php-src/...
#PHP
github.com/php/php-src/...
#PHP
October 14, 2025 at 8:54 AM
fun fact: PHP manages memory using reference counting, but xml extensions for some reason implement their own reference counting on top of general reference counting.
github.com/php/php-src/...
#PHP
github.com/php/php-src/...
#PHP
if you just happen to write a very basic jit compiler (for PHP, lets say) that generates simple binary that's calling into opcode handlers, you are limited by throughput of call/ret instructions, which is not that good.
margaras.k47.cz/@k47/statuse...
#PHP
margaras.k47.cz/@k47/statuse...
#PHP
October 2, 2025 at 10:57 PM
if you just happen to write a very basic jit compiler (for PHP, lets say) that generates simple binary that's calling into opcode handlers, you are limited by throughput of call/ret instructions, which is not that good.
margaras.k47.cz/@k47/statuse...
#PHP
margaras.k47.cz/@k47/statuse...
#PHP
if you want to write PHP from scratch, the first you have decide how you are going to manage memory
margaras.k47.cz/@k47/statuse...
#PHP
margaras.k47.cz/@k47/statuse...
#PHP
September 29, 2025 at 5:40 PM
if you want to write PHP from scratch, the first you have decide how you are going to manage memory
margaras.k47.cz/@k47/statuse...
#PHP
margaras.k47.cz/@k47/statuse...
#PHP
to fight against despair i need a project
so what if i reimplemented php from scratch?
margaras.k47.cz/@k47/statuse...
#PHP
so what if i reimplemented php from scratch?
margaras.k47.cz/@k47/statuse...
#PHP
September 27, 2025 at 12:44 PM
to fight against despair i need a project
so what if i reimplemented php from scratch?
margaras.k47.cz/@k47/statuse...
#PHP
so what if i reimplemented php from scratch?
margaras.k47.cz/@k47/statuse...
#PHP
fun little php detail margaras.k47.cz/@k47/statuse... #PHP
August 30, 2025 at 9:56 AM
fun little php detail margaras.k47.cz/@k47/statuse... #PHP
Podívejte, co plave na zdejších rybnících: Kachnička mandarinská. k47.cz/2025/kachnic...
August 8, 2025 at 12:43 PM
Podívejte, co plave na zdejších rybnících: Kachnička mandarinská. k47.cz/2025/kachnic...
php references are hilarious. not even this simple loop is not guaranteed to terminate
for ($i = 0; $i < 100; $i++) {
$a = 0;
}
not if $a and $i are references to each other
$a = 0;
$i = &$a;
#PHP
for ($i = 0; $i < 100; $i++) {
$a = 0;
}
not if $a and $i are references to each other
$a = 0;
$i = &$a;
#PHP
July 3, 2025 at 5:12 PM
php references are hilarious. not even this simple loop is not guaranteed to terminate
for ($i = 0; $i < 100; $i++) {
$a = 0;
}
not if $a and $i are references to each other
$a = 0;
$i = &$a;
#PHP
for ($i = 0; $i < 100; $i++) {
$a = 0;
}
not if $a and $i are references to each other
$a = 0;
$i = &$a;
#PHP
and there it is: GCC supports preserve_none attribute on x86
gcc.gnu.org/git/?p=gcc.g...
it's a feature precisely targeting tailcalling interpreters...
margaras.k47.cz/@k47/statuse...
gcc.gnu.org/git/?p=gcc.g...
it's a feature precisely targeting tailcalling interpreters...
margaras.k47.cz/@k47/statuse...
June 28, 2025 at 3:07 PM
and there it is: GCC supports preserve_none attribute on x86
gcc.gnu.org/git/?p=gcc.g...
it's a feature precisely targeting tailcalling interpreters...
margaras.k47.cz/@k47/statuse...
gcc.gnu.org/git/?p=gcc.g...
it's a feature precisely targeting tailcalling interpreters...
margaras.k47.cz/@k47/statuse...
this is pretty interesting:
imagine you have an array of sorted integers
if you rotate each integer one bit to the right, you need single pass of 1-bit radix sort to make the sequence sorted again...
margaras.k47.cz/@k47/statuse...
imagine you have an array of sorted integers
if you rotate each integer one bit to the right, you need single pass of 1-bit radix sort to make the sequence sorted again...
margaras.k47.cz/@k47/statuse...
June 24, 2025 at 3:26 PM
this is pretty interesting:
imagine you have an array of sorted integers
if you rotate each integer one bit to the right, you need single pass of 1-bit radix sort to make the sequence sorted again...
margaras.k47.cz/@k47/statuse...
imagine you have an array of sorted integers
if you rotate each integer one bit to the right, you need single pass of 1-bit radix sort to make the sequence sorted again...
margaras.k47.cz/@k47/statuse...
"I'm married to my job."
"So, what do you do?"
"Unemployed."
"So, what do you do?"
"Unemployed."
May 28, 2025 at 10:24 AM
"I'm married to my job."
"So, what do you do?"
"Unemployed."
"So, what do you do?"
"Unemployed."
PHP references are poison.
for example: what can we say about the type of variable $i?
for ($i = 0; $i < 1000; $i++) { f($i); }
one would expect that it can only be an integer, but no. function f can be something like this
function f(int &$arg) { $arg = "lol"; }
and then all bets are off.
#PHP
for example: what can we say about the type of variable $i?
for ($i = 0; $i < 1000; $i++) { f($i); }
one would expect that it can only be an integer, but no. function f can be something like this
function f(int &$arg) { $arg = "lol"; }
and then all bets are off.
#PHP
May 23, 2025 at 10:02 AM
PHP references are poison.
for example: what can we say about the type of variable $i?
for ($i = 0; $i < 1000; $i++) { f($i); }
one would expect that it can only be an integer, but no. function f can be something like this
function f(int &$arg) { $arg = "lol"; }
and then all bets are off.
#PHP
for example: what can we say about the type of variable $i?
for ($i = 0; $i < 1000; $i++) { f($i); }
one would expect that it can only be an integer, but no. function f can be something like this
function f(int &$arg) { $arg = "lol"; }
and then all bets are off.
#PHP
jsem bez peněz a teď mi ještě umírá laptop k47.cz/2025/pining-...
Laptop není mrtvý, ale umírá
Všechno jednou rozpadne. Ani můj laptop není výjimkou. Repasovaný thinkpad x270, který jsem za 3990 korun koupil v červenci 2023, začal minulý prosinec umírat. Nahodile zamrzal. Obrazovka zčernala,…
k47.cz
April 30, 2025 at 12:06 PM
jsem bez peněz a teď mi ještě umírá laptop k47.cz/2025/pining-...
error messages looks like this
ir_base[21].ops[1] insn reference (32825) is out of range
ir_base[21].ops[1] reference (32825) must be DATA
ir_base[21].ops[1] (32825) type is incompatible with...
reasonable if you just happen to be Dmitry Stogov, not if you are peasant like the rest of us
#PHP
ir_base[21].ops[1] insn reference (32825) is out of range
ir_base[21].ops[1] reference (32825) must be DATA
ir_base[21].ops[1] (32825) type is incompatible with...
reasonable if you just happen to be Dmitry Stogov, not if you are peasant like the rest of us
#PHP
April 13, 2025 at 12:29 PM
error messages looks like this
ir_base[21].ops[1] insn reference (32825) is out of range
ir_base[21].ops[1] reference (32825) must be DATA
ir_base[21].ops[1] (32825) type is incompatible with...
reasonable if you just happen to be Dmitry Stogov, not if you are peasant like the rest of us
#PHP
ir_base[21].ops[1] insn reference (32825) is out of range
ir_base[21].ops[1] reference (32825) must be DATA
ir_base[21].ops[1] (32825) type is incompatible with...
reasonable if you just happen to be Dmitry Stogov, not if you are peasant like the rest of us
#PHP
poking around in php jit is delightful. two key data types are declared like this:
typedef int32_t ir_ref;
typedef uintptr_t zend_jit_addr;
typesafety? never heard about it.
#PHP
typedef int32_t ir_ref;
typedef uintptr_t zend_jit_addr;
typesafety? never heard about it.
#PHP
April 13, 2025 at 12:27 PM
poking around in php jit is delightful. two key data types are declared like this:
typedef int32_t ir_ref;
typedef uintptr_t zend_jit_addr;
typesafety? never heard about it.
#PHP
typedef int32_t ir_ref;
typedef uintptr_t zend_jit_addr;
typesafety? never heard about it.
#PHP
there's a little memory exhaustion attack againt #php for you: send this 21 byte json "[[[[[[[[[[1]]]]]]]]]]" and json_decode allocates 2160 bytes of memory. that's 100x amplification. 10MB malicious json that forces php to allocate 1GB of memory can be gzipped to 25 kB.
April 5, 2025 at 9:28 AM
there's a little memory exhaustion attack againt #php for you: send this 21 byte json "[[[[[[[[[[1]]]]]]]]]]" and json_decode allocates 2160 bytes of memory. that's 100x amplification. 10MB malicious json that forces php to allocate 1GB of memory can be gzipped to 25 kB.
It's time for a new version of phpmod.d - my library for painless #PHP extensions in D language.
github.com/kaja47/phpmo...
Summary here margaras.k47.cz/@k47/statuse...
Briefly: docs, debug build, multiple PHP versions, parity testing with PHP source, -fno-druntime, variadic functions and more.
github.com/kaja47/phpmo...
Summary here margaras.k47.cz/@k47/statuse...
Briefly: docs, debug build, multiple PHP versions, parity testing with PHP source, -fno-druntime, variadic functions and more.
April 3, 2025 at 6:31 PM
It's time for a new version of phpmod.d - my library for painless #PHP extensions in D language.
github.com/kaja47/phpmo...
Summary here margaras.k47.cz/@k47/statuse...
Briefly: docs, debug build, multiple PHP versions, parity testing with PHP source, -fno-druntime, variadic functions and more.
github.com/kaja47/phpmo...
Summary here margaras.k47.cz/@k47/statuse...
Briefly: docs, debug build, multiple PHP versions, parity testing with PHP source, -fno-druntime, variadic functions and more.
Wikipedické faktoidy #13 (válka, atentáty, konspirace, další války a hyperinflace) k47.cz/2025/wiki-fa...
Wikipedické faktoidy #13 (válka, atentáty, konspirace, další války a hyperinflace)
Nikdy nevím, kam mě putování wikipedií zavede. Začal jsem na stránce o klapkách na oči a přes seznam atentátů na Hitlera a lokální války, co vypukly těsně po skončení první světové války, jsem se…
k47.cz
March 31, 2025 at 8:58 PM
Wikipedické faktoidy #13 (válka, atentáty, konspirace, další války a hyperinflace) k47.cz/2025/wiki-fa...
I'm preparing new version of phpmod.d library for simple development of native #PHP extensions (github.com/kaja47/phpmo...) and so it's time to recap news in the current one:
margaras.k47.cz/@k47/statuse...
margaras.k47.cz/@k47/statuse...
GitHub - kaja47/phpmod.d: Write PHP extensions without unending misery of C, macros and PHP build system.
Write PHP extensions without unending misery of C, macros and PHP build system. - kaja47/phpmod.d
github.com
March 18, 2025 at 2:25 PM
I'm preparing new version of phpmod.d library for simple development of native #PHP extensions (github.com/kaja47/phpmo...) and so it's time to recap news in the current one:
margaras.k47.cz/@k47/statuse...
margaras.k47.cz/@k47/statuse...