cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
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test_r5900_div1.c (2226B)

      1/*
      2 * Test R5900-specific DIV1.
      3 */
      4
      5#include <stdio.h>
      6#include <inttypes.h>
      7#include <assert.h>
      8
      9struct quotient_remainder { int32_t quotient, remainder; };
     10
     11static struct quotient_remainder div1(int32_t rs, int32_t rt)
     12{
     13    int32_t lo, hi;
     14
     15    __asm__ __volatile__ (
     16            "    div1 $0, %2, %3\n"
     17            "    mflo1 %0\n"
     18            "    mfhi1 %1\n"
     19            : "=r" (lo), "=r" (hi)
     20            : "r" (rs), "r" (rt));
     21
     22    assert(rs / rt == lo);
     23    assert(rs % rt == hi);
     24
     25    return (struct quotient_remainder) { .quotient = lo, .remainder = hi };
     26}
     27
     28static void verify_div1(int32_t rs, int32_t rt,
     29                        int32_t expected_quotient,
     30                        int32_t expected_remainder)
     31{
     32    struct quotient_remainder qr = div1(rs, rt);
     33
     34    assert(qr.quotient == expected_quotient);
     35    assert(qr.remainder == expected_remainder);
     36}
     37
     38static void verify_div1_negations(int32_t rs, int32_t rt,
     39                                  int32_t expected_quotient,
     40                                  int32_t expected_remainder)
     41{
     42    verify_div1(rs, rt, expected_quotient, expected_remainder);
     43    verify_div1(rs, -rt, -expected_quotient, expected_remainder);
     44    verify_div1(-rs, rt, -expected_quotient, -expected_remainder);
     45    verify_div1(-rs, -rt, expected_quotient, -expected_remainder);
     46}
     47
     48int main()
     49{
     50    verify_div1_negations(0, 1, 0, 0);
     51    verify_div1_negations(1, 1, 1, 0);
     52    verify_div1_negations(1, 2, 0, 1);
     53    verify_div1_negations(17, 19, 0, 17);
     54    verify_div1_negations(19, 17, 1, 2);
     55    verify_div1_negations(77773, 101, 770, 3);
     56
     57    verify_div1(-0x80000000,  1, -0x80000000, 0);
     58
     59    /*
     60     * Supplementary explanation from the Toshiba TX System RISC TX79 Core
     61     * Architecture manual, A-38 and B-7, https://wiki.qemu.org/File:C790.pdf
     62     *
     63     * Normally, when 0x80000000 (-2147483648) the signed minimum value is
     64     * divided by 0xFFFFFFFF (-1), the operation will result in an overflow.
     65     * However, in this instruction an overflow exception doesn't occur and
     66     * the result will be as follows:
     67     *
     68     * Quotient is 0x80000000 (-2147483648), and remainder is 0x00000000 (0).
     69     */
     70    verify_div1(-0x80000000, -1, -0x80000000, 0);
     71
     72    return 0;
     73}