150 lines
3.4 KiB
C
150 lines
3.4 KiB
C
// The OS/K Team licenses this file to you under the MIT license.
|
|
// See the LICENSE file in the project root for more information.
|
|
|
|
#include <pc/arch.h>
|
|
#include <in/arch_i.h>
|
|
|
|
bool eval_cond(ctx_t *ctx, uint cond)
|
|
{
|
|
bool neg = cond & (1 << 4);
|
|
bool ok;
|
|
|
|
cond &= ~(1 << 4);
|
|
|
|
switch (cond)
|
|
{
|
|
case CD_NONE: ok = 1; break;
|
|
|
|
case CD_C: ok = flg&CF; break;
|
|
case CD_O: ok = flg&OF; break;
|
|
case CD_Z: ok = flg&ZF; break;
|
|
case CD_S: ok = flg&SF; break;
|
|
case CD_P: ok = flg&PF; break;
|
|
|
|
case CD_A: ok = !(flg&CF || flg&ZF); break;
|
|
case CD_AE: ok = !(flg&CF); break;
|
|
|
|
case CD_B: ok = flg&CF; break;
|
|
case CD_BE: ok = flg&CF || flg&ZF; break;
|
|
|
|
case CD_G: ok = !(flg&ZF) && (!(flg&SF) == !(flg&OF)); break;
|
|
case CD_GE: ok = !(flg&SF) == !(flg&OF); break;
|
|
|
|
case CD_L: ok = !(flg&SF) != !(flg&OF); break;
|
|
case CD_LE: ok = flg&ZF || (!(flg&SF) != !(flg&OF)); break;
|
|
|
|
case CD_CXZ: ok = !rcx; break;
|
|
|
|
default:
|
|
_except(ctx, E_ILL, "Invalid COND value: 0x%x", (neg?cond|(1<<4):cond));
|
|
}
|
|
|
|
return neg ? !ok : !!ok;
|
|
}
|
|
|
|
//
|
|
// Executes an instruction
|
|
//
|
|
void exec_instr(ctx_t *ctx,
|
|
instr_t *in,
|
|
acc_t *p1,
|
|
acc_t *p2,
|
|
acc_t *p3,
|
|
bool lock,
|
|
bool rep)
|
|
{
|
|
bool out;
|
|
ulong r1 = 0, r2 = 0, r3 = 0;
|
|
|
|
// Global instruction counter
|
|
ctx->ninstrs++;
|
|
|
|
// Current frame instruction counter
|
|
rx2++; // since last frame change
|
|
rx1++; // since startup
|
|
|
|
//
|
|
// For REPs we evaluate the condition AFTER running the instruction,
|
|
// in a do ... while(cond) fashion
|
|
//
|
|
if (ctx->cond && in->func != i_b) // 'B' instruction is special
|
|
if (!rep && !eval_cond(ctx, ctx->cond))
|
|
return;
|
|
|
|
#ifndef NDEBUG
|
|
dump_instr(ctx, in, p1, p2, p3, lock, rep);
|
|
#endif
|
|
|
|
do_rep:
|
|
|
|
out = in->func(ctx, p1, p2, p3, &r1, &r2, &r3);
|
|
|
|
if (out)
|
|
{
|
|
if (p1->type == A_REG)
|
|
R(p1->reg) = r1;
|
|
|
|
else if (p1->type == A_IMM64)
|
|
_except(ctx, E_ACC, "Trying to output to an IMM64");
|
|
|
|
else
|
|
{
|
|
assert(ACC_IS_MEM(p1));
|
|
writemem(ctx, r1, p1->addr, p1->mlen);
|
|
}
|
|
}
|
|
|
|
if (out >= 2)
|
|
{
|
|
if (p2->type == A_REG)
|
|
R(p2->reg) = r2;
|
|
|
|
else if (p2->type == A_IMM64)
|
|
_except(ctx, E_ACC, "Trying to output to an IMM64");
|
|
|
|
else
|
|
{
|
|
assert(ACC_IS_MEM(p2));
|
|
writemem(ctx, r2, p2->addr, p2->mlen);
|
|
}
|
|
}
|
|
|
|
if (out >= 3)
|
|
{
|
|
if (p3->type == A_REG)
|
|
R(p3->reg) = r3;
|
|
|
|
else if (p3->type == A_IMM64)
|
|
_except(ctx, E_ACC, "Trying to output to an IMM64");
|
|
|
|
else
|
|
{
|
|
assert(ACC_IS_MEM(p3));
|
|
writemem(ctx, r3, p3->addr, p3->mlen);
|
|
}
|
|
}
|
|
|
|
if (rep)
|
|
{
|
|
// RCX remains untouched when condition fails
|
|
if (!eval_cond(ctx, ctx->cond))
|
|
return;
|
|
|
|
if (rcx > 0)
|
|
rcx--;
|
|
|
|
if (rcx == 0)
|
|
return;
|
|
|
|
ctx->ninstrs++;
|
|
|
|
#ifndef NDEBUG
|
|
// Show that we're REP'ing
|
|
dump_instr(ctx, in, p1, p2, p3, lock, rep);
|
|
#endif
|
|
|
|
goto do_rep;
|
|
}
|
|
}
|
|
|