RE: [Tinycc-devel] Wrong __int64 computation

[Christian Jullien]

In fact it was related to unsigned __int64 not signed __int64

The following patch modeled after TOK_DIV in x86_64-gen fixes, at least for
my case, this issue.
Could you please review the patch?

        } else {
            if (op == TOK_UDIV || op == TOK_UMOD) {
#if     1
                if ((vtop->type.t & VT_BTYPE) & VT_LLONG) {
                    o(0x9948); /* cqto */
                    o(0x48 + REX_BASE(fr));
                } else {
                    o(0x99); /* cltd */
                }
                o(0xf7); /* idiv fr, %eax */
                o(0xf0 + fr);
#else
                o(0xf7d231); /* xor %edx, %edx, div fr, %eax */
                o(0xf0 + fr);
#endif

Christian

-----Original Message-----
From: address@hidden
[mailto:address@hidden On Behalf Of
Christian Jullien
Sent: vendredi 18 décembre 2009 12:18
To: address@hidden
Subject: [Tinycc-devel] Wrong __int64 computation


Here is a simple test case that shows the bug:

#include <stdio.h>

int
main()
{
        int     i = 16;
        __int64 j = 16;
        unsigned __int64        n;

        // Use %p to show all bits

        n = 0x7fffffffffff;
        printf("Init:  n=%p, sizeof(n) = %d\n", n, sizeof(n)); // == 8 Ok!

        n = 0x7fffffffffff;
        n = n / i; // i is an int
        printf("Wrong: n=%p\n", n);

        n = 0x7fffffffffff;
        n = n / j; // j is an __int64
        printf("Wrong: n=%p\n", n);

        n = 0x7fffffffffff;
        n = n / 16;
        printf("Good:  n=%p\n", n);

}






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