articles/fast-quad-rotation/page.mmd

@@ -1,32 +0,0 @@
-Title:  Fast Quad Rotation
-Brief:  A better way to rotate quads around their centers.
-Date:   1722126213
-Tags:   Programming, Optimization, C
-CSS:    /style.css
-
-A similar in essence trick to [by pi rotation](/articles/vector-pi-rotation.html), but with delta calculated
-for some corner which is reused later with negation and coordinate swap.
-
-Scaling by `M_SQRT1_2` is there to retain the quad size (Pythagorean stuffs).
-
-### Code ###
-```c
-const t_fvec2 c = frect_center(sprite.rect);
-const t_fvec2 d = {
-    .x = (cosf(sprite.rotation + (float)M_PI_4) * sprite.rect.w) * (float)M_SQRT1_2,
-    .y = (sinf(sprite.rotation + (float)M_PI_4) * sprite.rect.h) * (float)M_SQRT1_2,
-};
-
-/* upper-left */
-const t_fvec2 v0 = { c.x - d.x, c.y - d.y };
-
-/* bottom-left */
-const t_fvec2 v1 = { c.x - d.y, c.y + d.x };
-
-/* bottom-right */
-const t_fvec2 v2 = { c.x + d.x, c.y + d.y };
-
-/* upper-right */
-const t_fvec2 v3 = { c.x + d.y, c.y - d.x };
-
-```

articles/rodata-lookup-caching/page.mmd

@@ -1,90 +0,0 @@
-Title:  Lookup Caching by .rodata Section String Inference
-Brief:  Rather hacky, but working way of string key lookup acceleration.
-Date:   1722127090
-Tags:   Programming, Optimization, C, Linux
-CSS:    /style.css
-
-While working on our immediate no-state engine, the need for texture lookup optimization arose.
-API is designed in a way where every single pushed triangle means resolution of texture by path.
-
-My insane mind came to such optimization then: detect is given path pointer is in .rodata and if so, -
-just lookup by hash of the pointer, not whole varying-size string. Constant time and all that.
-
-For that I ended up writing a limited ELF parsing routine that expects `/proc/self/exe`.
-Virtual address space randomization was tricky until I realized that
-`getauxval(AT_ENTRY) - ehdr.e_entry` could be used to get the base process address.
-
-After the section bounds are known, - it's as simple as checking `vm_start >= ptr && ptr < vm_end`.
-
-### Code ###
-```c
-/* code is fully self-contained, feel free to use it :) */
-
-#include <fcntl.h>
-#include <unistd.h>
-#include <sys/auxv.h>
-#include <elf.h>
-#include <linux/limits.h>
-
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-bool infer_elf_section_bounds(const char *const restrict name,
-                              const char **restrict vm_start,
-                              const char **restrict vm_end)
-{
-    bool result = false;
-    char buf[PATH_MAX];
-    ssize_t l = readlink("/proc/self/exe", buf, PATH_MAX);
-    if (l == -1)
-        goto ERR_CANT_READLINK;
-    buf[l] = 0; /* readlink() doesn't write a terminator */
-
-    int elf = open(buf, O_RDONLY);
-    if (elf == -1)
-        goto ERR_CANT_OPEN_SELF;
-
-    /* elf header */
-    Elf64_Ehdr ehdr;
-    read(elf, &ehdr, sizeof ehdr);
-    if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
-            ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
-            ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
-            ehdr.e_ident[EI_MAG3] != ELFMAG3)
-        goto ERR_NOT_ELF;
-
-    /* section header string table */
-    Elf64_Shdr shstrdr;
-    lseek(elf, ehdr.e_shoff + ehdr.e_shstrndx * sizeof (Elf64_Shdr), SEEK_SET);
-    read(elf, &shstrdr, sizeof shstrdr);
-    char *sh = malloc(shstrdr.sh_size);
-    lseek(elf, shstrdr.sh_offset, SEEK_SET);
-    read(elf, sh, shstrdr.sh_size);
-
-    /* walk sections searching for needed name */
-    lseek(elf, ehdr.e_shoff, SEEK_SET);
-    for (size_t s = 0; s < ehdr.e_shnum; ++s) {
-        Elf64_Shdr shdr;
-        read(elf, &shdr, sizeof shdr);
-
-        if (strcmp(&sh[shdr.sh_name], name) == 0) {
-            result = true;
-            *vm_start = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr;
-            *vm_end   = getauxval(AT_ENTRY) - ehdr.e_entry + (char *)shdr.sh_addr + shdr.sh_size;
-            break;
-        }
-    }
-
-    free(sh);
-
-ERR_NOT_ELF:
-    close(elf);
-
-ERR_CANT_OPEN_SELF:
-ERR_CANT_READLINK:
-    return result;
-}
-
-```

upload.sh

@@ -2,14 +2,6 @@
 
 set +e
 
-for arg in "$*"
-do
-  case "$arg" in
-    "--fresh") find ./html/ -type f -name '*.upload-checksum' -delete
-      ;;
-  esac
-done
-
 for cur in ./html/{*,*/*,*/*/*}; do
   if [ -f "$cur" ] && [[ ! "$cur" == *.upload-checksum ]]; then
     if [ -f "$cur.upload-checksum" ]; then