in reply to Re^4: 64-bit *nix/gcc expertise required
in thread 64-bit *nix/gcc expertise required (THIS IS NOT OFF TOPIC!)

I can do it with a pointer, but in that case, the pointer should be a pointer to a char, and not to an unsigned int.

#include <stdio.h>

#define ALIGN_BITS      (sizeof (void *) >> 1LL)
#define BIT_BITS         3LL
#define BYTE_BITS       14LL
#define SLOT_BITS       (sizeof (void *) * 8) - (ALIGN_BITS + BIT_BITS
+ + BYTE_BITS)
#define BYTES_PER_SLOT  1LL << BYTE_BITS
#define TRACKING_SLOTS  8192

typedef unsigned long long  ull_t;
typedef unsigned char      *ull_p;

int check_new (ull_p p)
{
    ull_t slot = ((ull_t)p >> (BYTE_BITS  + BIT_BITS + ALIGN_BITS));
    ull_t byte = ((ull_t)p >> (ALIGN_BITS + BIT_BITS)) & 0x00003fffLL;
    ull_t bit  = ((ull_t)p >>  ALIGN_BITS)             & 0x00000007LL;
    ull_t nop  =  (ull_t)p & 0x3LL;

    printf ("address: %012p slot: %012p byte: %4llx bit: %4llx nop: %l
+lx\n",
        p, (ull_p)slot, byte, bit, nop);
    return (1);
    } /* check_new */

int main (int argc, char *argv[])
{
    ull_p p;

    for (p = (ull_p)123456ULL; p < (ull_p)(1ULL << 34); p += (1ULL << 
+29))
        check_new (p);
    } /* main */

[download]

Will yield

address: 000000000001e240 slot: 0000000000000000 byte:  3c4 bit:    4 
+nop: 0
address: 000000002001e240 slot: 0000000000000100 byte:  3c4 bit:    4 
+nop: 0
address: 000000004001e240 slot: 0000000000000200 byte:  3c4 bit:    4 
+nop: 0
address: 000000006001e240 slot: 0000000000000300 byte:  3c4 bit:    4 
+nop: 0
address: 000000008001e240 slot: 0000000000000400 byte:  3c4 bit:    4 
+nop: 0
address: 00000000a001e240 slot: 0000000000000500 byte:  3c4 bit:    4 
+nop: 0
address: 00000000c001e240 slot: 0000000000000600 byte:  3c4 bit:    4 
+nop: 0
address: 00000000e001e240 slot: 0000000000000700 byte:  3c4 bit:    4 
+nop: 0
address: 000000010001e240 slot: 0000000000000800 byte:  3c4 bit:    4 
+nop: 0
address: 000000012001e240 slot: 0000000000000900 byte:  3c4 bit:    4 
+nop: 0
address: 000000014001e240 slot: 0000000000000a00 byte:  3c4 bit:    4 
+nop: 0
address: 000000016001e240 slot: 0000000000000b00 byte:  3c4 bit:    4 
+nop: 0
address: 000000018001e240 slot: 0000000000000c00 byte:  3c4 bit:    4 
+nop: 0
address: 00000001a001e240 slot: 0000000000000d00 byte:  3c4 bit:    4 
+nop: 0
address: 00000001c001e240 slot: 0000000000000e00 byte:  3c4 bit:    4 
+nop: 0
address: 00000001e001e240 slot: 0000000000000f00 byte:  3c4 bit:    4 
+nop: 0
address: 000000020001e240 slot: 0000000000001000 byte:  3c4 bit:    4 
+nop: 0
address: 000000022001e240 slot: 0000000000001100 byte:  3c4 bit:    4 
+nop: 0
address: 000000024001e240 slot: 0000000000001200 byte:  3c4 bit:    4 
+nop: 0
address: 000000026001e240 slot: 0000000000001300 byte:  3c4 bit:    4 
+nop: 0
address: 000000028001e240 slot: 0000000000001400 byte:  3c4 bit:    4 
+nop: 0
address: 00000002a001e240 slot: 0000000000001500 byte:  3c4 bit:    4 
+nop: 0
address: 00000002c001e240 slot: 0000000000001600 byte:  3c4 bit:    4 
+nop: 0
address: 00000002e001e240 slot: 0000000000001700 byte:  3c4 bit:    4 
+nop: 0
address: 000000030001e240 slot: 0000000000001800 byte:  3c4 bit:    4 
+nop: 0
address: 000000032001e240 slot: 0000000000001900 byte:  3c4 bit:    4 
+nop: 0
address: 000000034001e240 slot: 0000000000001a00 byte:  3c4 bit:    4 
+nop: 0
address: 000000036001e240 slot: 0000000000001b00 byte:  3c4 bit:    4 
+nop: 0
address: 000000038001e240 slot: 0000000000001c00 byte:  3c4 bit:    4 
+nop: 0
address: 00000003a001e240 slot: 0000000000001d00 byte:  3c4 bit:    4 
+nop: 0
address: 00000003c001e240 slot: 0000000000001e00 byte:  3c4 bit:    4 
+nop: 0
address: 00000003e001e240 slot: 0000000000001f00 byte:  3c4 bit:    4 
+nop: 0

[download]

And for short *:

address: 000000000001e240 slot: 0000000000000000 byte:  3c4 bit:    4 
+nop: 0
address: 000000004001e240 slot: 0000000000000200 byte:  3c4 bit:    4 
+nop: 0
address: 000000008001e240 slot: 0000000000000400 byte:  3c4 bit:    4 
+nop: 0
address: 00000000c001e240 slot: 0000000000000600 byte:  3c4 bit:    4 
+nop: 0
address: 000000010001e240 slot: 0000000000000800 byte:  3c4 bit:    4 
+nop: 0
address: 000000014001e240 slot: 0000000000000a00 byte:  3c4 bit:    4 
+nop: 0
address: 000000018001e240 slot: 0000000000000c00 byte:  3c4 bit:    4 
+nop: 0
address: 00000001c001e240 slot: 0000000000000e00 byte:  3c4 bit:    4 
+nop: 0
address: 000000020001e240 slot: 0000000000001000 byte:  3c4 bit:    4 
+nop: 0
address: 000000024001e240 slot: 0000000000001200 byte:  3c4 bit:    4 
+nop: 0
address: 000000028001e240 slot: 0000000000001400 byte:  3c4 bit:    4 
+nop: 0
address: 00000002c001e240 slot: 0000000000001600 byte:  3c4 bit:    4 
+nop: 0
address: 000000030001e240 slot: 0000000000001800 byte:  3c4 bit:    4 
+nop: 0
address: 000000034001e240 slot: 0000000000001a00 byte:  3c4 bit:    4 
+nop: 0
address: 000000038001e240 slot: 0000000000001c00 byte:  3c4 bit:    4 
+nop: 0

[download]

And for int *:

address: 000000000001e240 slot: 0000000000000000 byte:  3c4 bit:    4 
+nop: 0
address: 000000008001e240 slot: 0000000000000400 byte:  3c4 bit:    4 
+nop: 0
address: 000000010001e240 slot: 0000000000000800 byte:  3c4 bit:    4 
+nop: 0
address: 000000018001e240 slot: 0000000000000c00 byte:  3c4 bit:    4 
+nop: 0
address: 000000020001e240 slot: 0000000000001000 byte:  3c4 bit:    4 
+nop: 0
address: 000000028001e240 slot: 0000000000001400 byte:  3c4 bit:    4 
+nop: 0
address: 000000030001e240 slot: 0000000000001800 byte:  3c4 bit:    4 
+nop: 0
address: 000000038001e240 slot: 0000000000001c00 byte:  3c4 bit:    4 
+nop: 0

[download]

And for long long *:

address: 000000000001e240 slot: 0000000000000000 byte:  3c4 bit:    4 
+nop: 0
address: 000000010001e240 slot: 0000000000000800 byte:  3c4 bit:    4 
+nop: 0
address: 000000020001e240 slot: 0000000000001000 byte:  3c4 bit:    4 
+nop: 0
address: 000000030001e240 slot: 0000000000001800 byte:  3c4 bit:    4 
+nop: 0

[download]

Enjoy, Have FUN! H.Merijn

Replies are listed 'Best First'.
Re^6: 64-bit *nix/gcc expertise required
by BrowserUk (Patriarch) on Dec 24, 2010 at 17:15 UTC

    That looks a lot closer, but what happens if compile that for 32-bit? (The for loop will never terminate, but that's inconsequential to the real use>)

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

      That - as expected - gives us warnings:

      "test.c", line 21: warning #2171-D: invalid type conversion
        p, (ull_p)slot, byte, bit, nop);
           ^

"test.c", line 29: warning #2171-D: invalid type conversion
      for (p = (ull_p)123456ULL; p < (ull_p)(1ULL << 34); p += (1ULL <
+< 29))
               ^

"test.c", line 29: warning #2171-D: invalid type conversion
      for (p = (ull_p)123456ULL; p < (ull_p)(1ULL << 34); p += (1ULL <
+< 29))
                                     ^

"test.c", line 29: remark #4274-D: comparison of pointer with integer 
+zero
      for (p = (ull_p)123456ULL; p < (ull_p)(1ULL << 34); p += (1ULL <
+< 29))
                                   ^

      [download]

      And when running ...

      ELF-32 executable object file - IA64

No output at all

      [download]

      Enjoy, Have FUN! H.Merijn
[reply]
[d/l]
[select]

        Tux Many thanks for your assistance. Up for a bit more?

        In theory, based on my reading the gcc headers, this should compile clean under 32/64-bit. It probably won't, but once you recover from your seasonal revelries, I'd appreciated seeing the warnings/errors produced on your various platforms. 

        #include <stdio.h>
#define __STDC_LIMIT_MACROS
#include <stdint.h>
#include <stddef.h>

#define ALIGN_BITS  ( sizeof(void*) >> __UINT64_C( 1 ) )
#define BIT_BITS     __UINT64_C( 3 )
#define BYTE_BITS   __UINT64_C( 14 )
#define SLOT_BITS   ( sizeof( void*) * 8 ) - ( ALIGN_BITS + BIT_BITS +
+ BYTE_BITS )
#define BYTES_PER_SLOT  __UINT64_C( 1 ) << BYTE_BITS
#define TRACKING_SLOTS  8192 // max. 8192 for 4GB/32-bit machine

int check_new( uintptr_t p ) {
    ptrdiff_t slot = ( p >> (BYTE_BITS + BIT_BITS + ALIGN_BITS) );
    ptrdiff_t byte = ( p >> (ALIGN_BITS + BIT_BITS)) & __UINT64_C( 0x0
+0003fff )
    ptrdiff_t bit  = ( p >> ALIGN_BITS)              & __UINT64_C( 0x0
+0000007 );
    ptrdiff_t nop  =   p                             & __UINT64_C( 0x3
+        );

    printf(
        "address: %p slot: %p byte: %4x bit: %4x nop:%x\n",
        p, slot, byte, bit, nop
    );
    return 1;
}

void main( void ) {
    uintptr_t p;

    for( p = __UINT64_C( 123456 ); p < ( __UINT64_C( 1 ) << 34 ); p +=
+ ( __UINT64_C( 1 ) << 29 ) ) {
        check_new( p );
    }
}

        [download]
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
        Change 34 to 31 to get some output.
[reply]

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