/* Print out the sib byte of the parsed instruction in the given decoder state
* to the given file.
*/
static void SibPrint(const NCDecoderInst* dinst, struct Gio* fp) {
uint8_t sib = NCInstBytesByte(&dinst->inst_bytes, NCSibOffset(dinst));
if (!dinst->inst.hassibbyte) {
/* This should not happen. */
gprintf(fp, "?");
} else if (sib_ss(sib) == 0) {
if (sib_base(sib) == 5) {
/* This code is JUST WRONG!. However, I am not fixing since
* the decoder printer is broken in so many other ways!. See tables
* 2-1 and 2-2 of "Intel 64 and IA-32 Architectures Software Developer's
* Manual" for details of what should be done (there are
* 3 cases, depending on the value of the mod field of the modrm
* byte).
* Note: While the changes here are not correct, they at least make
* sure that we process bytes that are actually in the instruction.
* That is, the code doesn't accidentally walk off the end of the
* parsed instruction.
*/
gprintf(fp, "[0x%x]", DispValue32(dinst));
} else {
/* Has a base register */
if (sib_index(sib) == 4) {
/* No index */
gprintf(fp, "[%s]", gp_regs[sib_base(sib)]);
} else {
gprintf(fp, "[%s + %s]",
gp_regs[sib_base(sib)],
gp_regs[sib_index(sib)]);
}
}
} else {
if (sib_index(sib) == 4) {
/* No index */
gprintf(fp, "[%s]", gp_regs[sib_base(sib)]);
} else {
gprintf(fp, "[%s + %d * %s]",
gp_regs[sib_base(sib)],
1 << sib_ss(sib),
gp_regs[sib_index(sib)]);
}
}
}
/*
* Read address at location and return updated location.
*/
db_addr_t
db_read_address(db_addr_t loc, int short_addr, int regmodrm, int rex,
struct i_addr *addrp)
{
int mod, rm, sib, index, disp, size;
size = (short_addr ? LONG : QUAD);
mod = f_mod(regmodrm);
rm = f_rm(regmodrm, rex);
if (mod == 3) {
addrp->is_reg = TRUE;
addrp->disp = rm;
return (loc);
}
addrp->is_reg = FALSE;
addrp->index = 0;
if (rm == 4 || rm == 12) {
get_value_inc(sib, loc, 1, FALSE);
rm = sib_base(sib, rex);
index = sib_index(sib, rex);
if (index != 4)
addrp->index = db_reg[size][index];
addrp->ss = sib_ss(sib);
}
switch (mod) {
case 0:
if (rm == 5) {
get_value_inc(addrp->disp, loc, 4, FALSE);
addrp->base = 0;
} else {
addrp->disp = 0;
addrp->base = db_reg[size][rm];
}
break;
case 1:
get_value_inc(disp, loc, 1, TRUE);
addrp->disp = disp;
addrp->base = db_reg[size][rm];
break;
case 2:
get_value_inc(disp, loc, 4, FALSE);
addrp->disp = disp;
addrp->base = db_reg[size][rm];
break;
}
return (loc);
}
/*
* Read address at location and return updated location.
*/
db_addr_t
db_read_address(db_addr_t loc, int short_addr, int regmodrm,
struct i_addr *addrp)
{
int mod, rm, sib, index, disp;
mod = f_mod(regmodrm);
rm = f_rm(regmodrm);
if (mod == 3) {
addrp->is_reg = TRUE;
addrp->disp = rm;
return (loc);
}
addrp->is_reg = FALSE;
addrp->index = 0;
if (short_addr) {
addrp->index = 0;
addrp->ss = 0;
switch (mod) {
case 0:
if (rm == 6) {
get_value_inc(disp, loc, 2, FALSE);
addrp->disp = disp;
addrp->base = 0;
} else {
addrp->disp = 0;
addrp->base = db_index_reg_16[rm];
}
break;
case 1:
get_value_inc(disp, loc, 1, TRUE);
disp &= 0xffff;
addrp->disp = disp;
addrp->base = db_index_reg_16[rm];
break;
case 2:
get_value_inc(disp, loc, 2, FALSE);
addrp->disp = disp;
addrp->base = db_index_reg_16[rm];
break;
}
} else {
if (rm == 4) {
get_value_inc(sib, loc, 1, FALSE);
rm = sib_base(sib);
index = sib_index(sib);
if (index != 4)
addrp->index = db_reg[LONG][index];
addrp->ss = sib_ss(sib);
}
switch (mod) {
case 0:
if (rm == 5) {
get_value_inc(addrp->disp, loc, 4, FALSE);
addrp->base = 0;
} else {
addrp->disp = 0;
addrp->base = db_reg[LONG][rm];
}
break;
case 1:
get_value_inc(disp, loc, 1, TRUE);
addrp->disp = disp;
addrp->base = db_reg[LONG][rm];
break;
case 2:
get_value_inc(disp, loc, 4, FALSE);
addrp->disp = disp;
addrp->base = db_reg[LONG][rm];
break;
}
}
return (loc);
}
/*
* Read address at location and return updated location.
*/
static db_addr_t
db_read_address(db_addr_t loc, int short_addr, int rex, int regmodrm,
struct i_addr *addrp)
{
int mod, rm, sib, index, disp, size, have_sib;
mod = f_mod(rex, regmodrm);
rm = f_rm(rex, regmodrm);
if (mod == 3) {
addrp->is_reg = TRUE;
addrp->disp = rm;
return (loc);
}
addrp->is_reg = FALSE;
addrp->index = NULL;
if (short_addr)
size = LONG;
else
size = QUAD;
if ((rm & 0x7) == 4) {
get_value_inc(sib, loc, 1, FALSE);
rm = sib_base(rex, sib);
index = sib_index(rex, sib);
if (index != 4)
addrp->index = db_reg[1][size][index];
addrp->ss = sib_ss(rex, sib);
have_sib = 1;
} else
have_sib = 0;
switch (mod) {
case 0:
if (rm == 5) {
get_value_inc(addrp->disp, loc, 4, FALSE);
if (have_sib)
addrp->base = NULL;
else if (short_addr)
addrp->base = "%eip";
else
addrp->base = "%rip";
} else {
addrp->disp = 0;
addrp->base = db_reg[1][size][rm];
}
break;
case 1:
get_value_inc(disp, loc, 1, TRUE);
addrp->disp = disp;
addrp->base = db_reg[1][size][rm];
break;
case 2:
get_value_inc(disp, loc, 4, FALSE);
addrp->disp = disp;
addrp->base = db_reg[1][size][rm];
break;
}
return (loc);
}