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nullplan wrote:Well, what does happen? Have you asked a debugger? Is it possible the memset just takes a while?

The code looks reasonable enough, except of course for the fact that you don't have the four mem* functions GCC requires even in freestanding mode. You must have an implementation of memset(), memcpy(), memcmp(), and memmove(). You only have memory_set(), which isn't the same.

The ISO C90 functions abort, abs, acos, asin, atan2, atan, calloc, ceil, cosh, cos, exit, exp, fabs, floor, fmod, fprintf, fputs, frexp, fscanf, isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, tolower, toupper, labs, ldexp, log10, log, malloc, memchr, memcmp, memcpy, memset, modf, pow, printf, putchar, puts, scanf, sinh, sin, snprintf, sprintf, sqrt, sscanf, strcat, strchr, strcmp, strcpy, strcspn, strlen, strncat, strncmp, strncpy, strpbrk, strrchr, strspn, strstr, tanh, tan, vfprintf, vprintf and vsprintf are all recognized as built-in functions unless -fno-builtin is specified (or -fno-builtin-function is specified for an individual function). All of these functions have corresponding versions prefixed with __builtin_.

bzt wrote:That's not entirely true. First without a memset() implementation the code wouldn't compile and link in the first place. Second, gcc has a dirty, totally libgcc independent hack for the mem functions (which works in freestanding mode too), it includes the __builtin_memset() in the final executable if memset() implementation otherwise not found. This is highly non-standard, and for example Clang doesn't do it.

nullplan wrote:Well, what does happen? Have you asked a debugger? Is it possible the memset just takes a while?

The code looks reasonable enough, except of course for the fact that you don't have the four mem* functions GCC requires even in freestanding mode. You must have an implementation of memset(), memcpy(), memcmp(), and memmove(). You only have memory_set(), which isn't the same.

Here is my compiler support library. In case it actually is creative enough to even get a copyright, it is hereby released into the public domain. Optimization is left as an excercise to the reader, if need be. Oh yeah, and it is C, at least C99, and won't work as C++.

Code: Select all

#include <stddef.h>

void *memcpy(void* restrict a, const void *restrict b, size_t len) {
    unsigned char *d = a;
    const unsigned char *s = b;

    if (d != s) {
        while (len--)
            *d++ = *s++;
    }
    return a;
}

void *memmove(void* a, const void* b, size_t len) {
    unsigned char *d = a;
    const unsigned char *s = b;
    if (d <= s || d >= s + len)
        return memcpy(d, s, len);
    d += len;
    s += len;
    while (len--)
        *--d = *--s;
    return a;
}

void *memset(void *a, int v, size_t len) {
    unsigned char *d = a;
    while (len--)
        *d++ = v;
    return a;
}

int memcmp(const void * restrict a, const void * restrict b, size_t len) {
    int r = 0;
    const unsigned char *x = a;
    const unsigned char *y = b;

    while (len--) {
        r = *x - *y;
        if (r)
            return r;
        x++, y++;
    }
    return 0;
}

 // Now, enable paging!
    switch_page_directory(kernel_directory);
    print_s("test");
    // Initialise the kernel heap.
    kheap = create_heap(KHEAP_START, KHEAP_START+KHEAP_INITIAL_SIZE, 0xCFFFF000, 0, 0);
    print_s("testFInal");
}

Shvets04 wrote:What information you want to get from debuger?

The code from initialise_pagint()

Code: Select all

 // Now, enable paging!
    switch_page_directory(kernel_directory);
    print_s("test");
    // Initialise the kernel heap.
    kheap = create_heap(KHEAP_START, KHEAP_START+KHEAP_INITIAL_SIZE, 0xCFFFF000, 0, 0);
    print_s("testFInal");
}

"test" is being print, but "testFinal" not.

Octocontrabass wrote:I don't see where you're getting that from the documentation. The __builtin_memset() function doesn't exist

gcc manual wrote:...memset,...
All of these functions have corresponding versions prefixed with __builtin_.