/*
* decode_moffset
* Decode offset-only memory operand
*/
static void
decode_moffset(struct ud *u, unsigned int size, struct ud_operand *opr)
{
opr->type = UD_OP_MEM;
opr->size = resolve_operand_size(u, size);
decode_mem_disp(u, u->adr_mode, opr);
}
static void
decode_reg(struct ud *u,
struct ud_operand *opr,
int type,
int num,
int size)
{
int reg;
size = resolve_operand_size(u, size);
switch (type) {
case REGCLASS_GPR : reg = decode_gpr(u, size, num); break;
case REGCLASS_MMX : reg = UD_R_MM0 + (num & 7); break;
case REGCLASS_XMM : reg = UD_R_XMM0 + num; break;
case REGCLASS_CR : reg = UD_R_CR0 + num; break;
case REGCLASS_DB : reg = UD_R_DR0 + num; break;
case REGCLASS_SEG : {
/*
* Only 6 segment registers, anything else is an error.
*/
if ((num & 7) > 5) {
UDERR(u, "invalid segment register value\n");
return;
} else {
reg = UD_R_ES + (num & 7);
}
break;
}
default:
UD_ASSERT(!"invalid register type");
return;
}
opr->type = UD_OP_REG;
opr->base = reg;
opr->size = size;
}
/* -----------------------------------------------------------------------------
* decode_imm() - Decodes Immediate values.
* -----------------------------------------------------------------------------
*/
static void
decode_imm(struct ud* u, unsigned int s, struct ud_operand *op)
{
op->size = (uint8_t) resolve_operand_size(u, s);
op->type = UD_OP_IMM;
switch (op->size) {
case 8: op->lval.sbyte = inp_uint8(u); break;
case 16: op->lval.uword = inp_uint16(u); break;
case 32: op->lval.udword = inp_uint32(u); break;
default: return;
}
}
/*
* decode_modrm_reg
*
* Decodes reg field of mod/rm byte
*
*/
static void
decode_modrm_reg(struct ud *u,
struct ud_operand *operand,
unsigned int type,
unsigned int size)
{
uint8_t reg = (REX_R(u->pfx_rex) << 3) | MODRM_REG(modrm(u));
operand->type = UD_OP_REG;
operand->size = resolve_operand_size(u, size);
if (type == T_GPR) {
operand->base = decode_gpr(u, operand->size, reg);
} else {
operand->base = resolve_reg(u, type, reg);
}
}
/* -----------------------------------------------------------------------------
* decode_o() - Decodes offset
* -----------------------------------------------------------------------------
*/
static void
decode_o(struct ud* u, unsigned int s, struct ud_operand *op)
{
switch (u->adr_mode) {
case 32:
op->offset = 32;
op->lval.udword = inp_uint32(u);
break;
case 16:
op->offset = 16;
op->lval.uword = inp_uint16(u);
break;
default:
return;
}
op->type = UD_OP_MEM;
op->size = (uint8_t)resolve_operand_size(u, s);
}
/* -----------------------------------------------------------------------------
* decode_gpr() - Returns decoded General Purpose Register
* -----------------------------------------------------------------------------
*/
static enum ud_type
decode_gpr(register struct ud* u, unsigned int s, unsigned char rm)
{
s = resolve_operand_size(u, s);
switch (s) {
case SZ_DP:
case 32:
return UD_R_EAX + rm;
case SZ_WP:
case 16:
return UD_R_AX + rm;
case 8:
if (u->dis_mode == 64 && u->pfx_rex) {
if (rm >= 4)
return UD_R_SPL + (rm-4);
return UD_R_AL + rm;
} else return UD_R_AL + rm;
default:
return 0;
}
}
/*
* decode_modrm_rm
*
* Decodes rm field of mod/rm byte
*
*/
static void
decode_modrm_rm(struct ud *u,
struct ud_operand *op,
unsigned char type,
unsigned int size)
{
unsigned char mod, rm, reg;
/* get mod, r/m and reg fields */
mod = MODRM_MOD(modrm(u));
rm = (REX_B(u->pfx_rex) << 3) | MODRM_RM(modrm(u));
reg = (REX_R(u->pfx_rex) << 3) | MODRM_REG(modrm(u));
op->size = resolve_operand_size(u, size);
/*
* If mod is 11b, then the modrm.rm specifies a register.
*
*/
if (mod == 3) {
op->type = UD_OP_REG;
if (type == T_GPR) {
op->base = decode_gpr(u, op->size, rm);
} else {
op->base = resolve_reg(u, type, (REX_B(u->pfx_rex) << 3) | (rm & 7));
}
return;
}
/*
* !11 => Memory Address
*/
op->type = UD_OP_MEM;
if (u->adr_mode == 64) {
op->base = UD_R_RAX + rm;
if (mod == 1) {
op->offset = 8;
} else if (mod == 2) {
op->offset = 32;
} else if (mod == 0 && (rm & 7) == 5) {
op->base = UD_R_RIP;
op->offset = 32;
} else {
op->offset = 0;
}
/*
* Scale-Index-Base (SIB)
*/
if ((rm & 7) == 4) {
inp_next(u);
op->scale = (1 << SIB_S(inp_curr(u))) & ~1;
op->index = UD_R_RAX + (SIB_I(inp_curr(u)) | (REX_X(u->pfx_rex) << 3));
op->base = UD_R_RAX + (SIB_B(inp_curr(u)) | (REX_B(u->pfx_rex) << 3));
/* special conditions for base reference */
if (op->index == UD_R_RSP) {
op->index = UD_NONE;
op->scale = UD_NONE;
}
if (op->base == UD_R_RBP || op->base == UD_R_R13) {
if (mod == 0) {
op->base = UD_NONE;
}
if (mod == 1) {
op->offset = 8;
} else {
op->offset = 32;
}
}
}
} else if (u->adr_mode == 32) {
op->base = UD_R_EAX + rm;
if (mod == 1) {
op->offset = 8;
} else if (mod == 2) {
op->offset = 32;
} else if (mod == 0 && rm == 5) {
op->base = UD_NONE;
op->offset = 32;
} else {
op->offset = 0;
}
/* Scale-Index-Base (SIB) */
if ((rm & 7) == 4) {
inp_next(u);
op->scale = (1 << SIB_S(inp_curr(u))) & ~1;
op->index = UD_R_EAX + (SIB_I(inp_curr(u)) | (REX_X(u->pfx_rex) << 3));
op->base = UD_R_EAX + (SIB_B(inp_curr(u)) | (REX_B(u->pfx_rex) << 3));
if (op->index == UD_R_ESP) {
op->index = UD_NONE;
op->scale = UD_NONE;
}
/* special condition for base reference */
if (op->base == UD_R_EBP) {
if (mod == 0) {
op->base = UD_NONE;
}
if (mod == 1) {
op->offset = 8;
} else {
op->offset = 32;
}
}
}
} else {
const unsigned int bases[] = { UD_R_BX, UD_R_BX, UD_R_BP, UD_R_BP,
UD_R_SI, UD_R_DI, UD_R_BP, UD_R_BX };
const unsigned int indices[] = { UD_R_SI, UD_R_DI, UD_R_SI, UD_R_DI,
UD_NONE, UD_NONE, UD_NONE, UD_NONE };
op->base = bases[rm & 7];
op->index = indices[rm & 7];
if (mod == 0 && rm == 6) {
op->offset= 16;
op->base = UD_NONE;
} else if (mod == 1) {
op->offset = 8;
} else if (mod == 2) {
op->offset = 16;
}
}
/*
* extract offset, if any
*/
switch (op->offset) {
case 8 : op->lval.ubyte = inp_uint8(u); break;
case 16: op->lval.uword = inp_uint16(u); break;
case 32: op->lval.udword = inp_uint32(u); break;
case 64: op->lval.uqword = inp_uint64(u); break;
default: break;
}
}
/*
* decode_modrm_rm
*
* Decodes rm field of mod/rm byte
*
*/
static void
decode_modrm_rm(struct ud *u,
struct ud_operand *op,
unsigned char type, /* register type */
unsigned int size) /* operand size */
{
size_t offset = 0;
unsigned char mod, rm;
/* get mod, r/m and reg fields */
mod = MODRM_MOD(modrm(u));
rm = (REX_B(u->pfx_rex) << 3) | MODRM_RM(modrm(u));
/*
* If mod is 11b, then the modrm.rm specifies a register.
*
*/
if (mod == 3) {
decode_reg(u, op, type, rm, size);
return;
}
/*
* !11b => Memory Address
*/
op->type = UD_OP_MEM;
op->size = resolve_operand_size(u, size);
if (u->adr_mode == 64) {
op->base = UD_R_RAX + rm;
if (mod == 1) {
offset = 8;
} else if (mod == 2) {
offset = 32;
} else if (mod == 0 && (rm & 7) == 5) {
op->base = UD_R_RIP;
offset = 32;
} else {
offset = 0;
}
/*
* Scale-Index-Base (SIB)
*/
if ((rm & 7) == 4) {
inp_next(u);
op->scale = (1 << SIB_S(inp_curr(u))) & ~1;
op->index = UD_R_RAX + (SIB_I(inp_curr(u)) | (REX_X(u->pfx_rex) << 3));
op->base = UD_R_RAX + (SIB_B(inp_curr(u)) | (REX_B(u->pfx_rex) << 3));
/* special conditions for base reference */
if (op->index == UD_R_RSP) {
op->index = UD_NONE;
op->scale = UD_NONE;
}
if (op->base == UD_R_RBP || op->base == UD_R_R13) {
if (mod == 0) {
op->base = UD_NONE;
}
if (mod == 1) {
offset = 8;
} else {
offset = 32;
}
}
}
} else if (u->adr_mode == 32) {
op->base = UD_R_EAX + rm;
if (mod == 1) {
offset = 8;
} else if (mod == 2) {
offset = 32;
} else if (mod == 0 && rm == 5) {
op->base = UD_NONE;
offset = 32;
} else {
offset = 0;
}
/* Scale-Index-Base (SIB) */
if ((rm & 7) == 4) {
inp_next(u);
op->scale = (1 << SIB_S(inp_curr(u))) & ~1;
op->index = UD_R_EAX + (SIB_I(inp_curr(u)) | (REX_X(u->pfx_rex) << 3));
op->base = UD_R_EAX + (SIB_B(inp_curr(u)) | (REX_B(u->pfx_rex) << 3));
if (op->index == UD_R_ESP) {
op->index = UD_NONE;
op->scale = UD_NONE;
}
/* special condition for base reference */
if (op->base == UD_R_EBP) {
if (mod == 0) {
op->base = UD_NONE;
}
if (mod == 1) {
offset = 8;
} else {
offset = 32;
}
}
}
} else {
const unsigned int bases[] = { UD_R_BX, UD_R_BX, UD_R_BP, UD_R_BP,
UD_R_SI, UD_R_DI, UD_R_BP, UD_R_BX };
const unsigned int indices[] = { UD_R_SI, UD_R_DI, UD_R_SI, UD_R_DI,
UD_NONE, UD_NONE, UD_NONE, UD_NONE };
op->base = bases[rm & 7];
op->index = indices[rm & 7];
if (mod == 0 && rm == 6) {
offset = 16;
op->base = UD_NONE;
} else if (mod == 1) {
offset = 8;
} else if (mod == 2) {
offset = 16;
}
}
if (offset) {
decode_mem_disp(u, offset, op);
}
}
/* -----------------------------------------------------------------------------
* disasm_operands() - Disassembles Operands.
* -----------------------------------------------------------------------------
*/
static int disasm_operands(register struct ud* u)
{
/* mopXt = map entry, operand X, type; */
enum ud_operand_code mop1t = u->itab_entry->operand1.type;
enum ud_operand_code mop2t = u->itab_entry->operand2.type;
enum ud_operand_code mop3t = u->itab_entry->operand3.type;
/* mopXs = map entry, operand X, size */
unsigned int mop1s = u->itab_entry->operand1.size;
unsigned int mop2s = u->itab_entry->operand2.size;
unsigned int mop3s = u->itab_entry->operand3.size;
/* iop = instruction operand */
register struct ud_operand* iop = u->operand;
switch(mop1t) {
case OP_A :
decode_a(u, &(iop[0]));
break;
/* M[b] ... */
case OP_M :
if (MODRM_MOD(inp_peek(u)) == 3)
u->error= 1;
/* E, G/P/V/I/CL/1/S */
case OP_E :
if (mop2t == OP_G) {
decode_modrm(u, &(iop[0]), mop1s, T_GPR, &(iop[1]), mop2s, T_GPR);
if (mop3t == OP_I)
decode_imm(u, mop3s, &(iop[2]));
else if (mop3t == OP_CL) {
iop[2].type = UD_OP_REG;
iop[2].base = UD_R_CL;
iop[2].size = 8;
}
}
else if (mop2t == OP_P)
decode_modrm(u, &(iop[0]), mop1s, T_GPR, &(iop[1]), mop2s, T_MMX);
else if (mop2t == OP_V)
decode_modrm(u, &(iop[0]), mop1s, T_GPR, &(iop[1]), mop2s, T_XMM);
else if (mop2t == OP_S)
decode_modrm(u, &(iop[0]), mop1s, T_GPR, &(iop[1]), mop2s, T_SEG);
else {
decode_modrm(u, &(iop[0]), mop1s, T_GPR, NULL, 0, T_NONE);
if (mop2t == OP_CL) {
iop[1].type = UD_OP_REG;
iop[1].base = UD_R_CL;
iop[1].size = 8;
} else if (mop2t == OP_I1) {
iop[1].type = UD_OP_CONST;
u->operand[1].lval.udword = 1;
} else if (mop2t == OP_I) {
decode_imm(u, mop2s, &(iop[1]));
}
}
break;
/* G, E/PR[,I]/VR */
case OP_G :
if (mop2t == OP_M) {
if (MODRM_MOD(inp_peek(u)) == 3)
u->error= 1;
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_GPR);
} else if (mop2t == OP_E) {
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_GPR);
if (mop3t == OP_I)
decode_imm(u, mop3s, &(iop[2]));
} else if (mop2t == OP_PR) {
decode_modrm(u, &(iop[1]), mop2s, T_MMX, &(iop[0]), mop1s, T_GPR);
if (mop3t == OP_I)
decode_imm(u, mop3s, &(iop[2]));
} else if (mop2t == OP_VR) {
if (MODRM_MOD(inp_peek(u)) != 3)
u->error = 1;
decode_modrm(u, &(iop[1]), mop2s, T_XMM, &(iop[0]), mop1s, T_GPR);
} else if (mop2t == OP_W)
decode_modrm(u, &(iop[1]), mop2s, T_XMM, &(iop[0]), mop1s, T_GPR);
break;
/* AL..BH, I/O/DX */
case OP_AL : case OP_CL : case OP_DL : case OP_BL :
case OP_AH : case OP_CH : case OP_DH : case OP_BH :
iop[0].type = UD_OP_REG;
iop[0].base = UD_R_AL + (mop1t - OP_AL);
iop[0].size = 8;
if (mop2t == OP_I)
decode_imm(u, mop2s, &(iop[1]));
else if (mop2t == OP_DX) {
iop[1].type = UD_OP_REG;
iop[1].base = UD_R_DX;
iop[1].size = 16;
}
else if (mop2t == OP_O)
decode_o(u, mop2s, &(iop[1]));
break;
/* rAX[r8]..rDI[r15], I/rAX..rDI/O */
case OP_rAXr8 : case OP_rCXr9 : case OP_rDXr10 : case OP_rBXr11 :
case OP_rSPr12: case OP_rBPr13: case OP_rSIr14 : case OP_rDIr15 :
case OP_rAX : case OP_rCX : case OP_rDX : case OP_rBX :
case OP_rSP : case OP_rBP : case OP_rSI : case OP_rDI :
iop[0].type = UD_OP_REG;
iop[0].base = resolve_gpr64(u, mop1t);
if (mop2t == OP_I)
decode_imm(u, mop2s, &(iop[1]));
else if (mop2t >= OP_rAX && mop2t <= OP_rDI) {
iop[1].type = UD_OP_REG;
iop[1].base = resolve_gpr64(u, mop2t);
}
else if (mop2t == OP_O) {
decode_o(u, mop2s, &(iop[1]));
iop[0].size = (uint8_t)resolve_operand_size(u, mop2s);
}
break;
/* AL[r8b]..BH[r15b], I */
case OP_ALr8b : case OP_CLr9b : case OP_DLr10b : case OP_BLr11b :
case OP_AHr12b: case OP_CHr13b: case OP_DHr14b : case OP_BHr15b :
{
ud_type_t gpr = (mop1t - OP_ALr8b) + UD_R_AL +
(REX_B(u->pfx_rex) << 3);
if (UD_R_AH <= gpr && u->pfx_rex)
gpr = gpr + 4;
iop[0].type = UD_OP_REG;
iop[0].base = gpr;
if (mop2t == OP_I)
decode_imm(u, mop2s, &(iop[1]));
break;
}
/* eAX..eDX, DX/I */
case OP_eAX : case OP_eCX : case OP_eDX : case OP_eBX :
case OP_eSP : case OP_eBP : case OP_eSI : case OP_eDI :
iop[0].type = UD_OP_REG;
iop[0].base = resolve_gpr32(u, mop1t);
if (mop2t == OP_DX) {
iop[1].type = UD_OP_REG;
iop[1].base = UD_R_DX;
iop[1].size = 16;
} else if (mop2t == OP_I)
decode_imm(u, mop2s, &(iop[1]));
break;
/* ES..GS */
case OP_ES : case OP_CS : case OP_DS :
case OP_SS : case OP_FS : case OP_GS :
/* in 64bits mode, only fs and gs are allowed */
if (u->dis_mode == 64)
if (mop1t != OP_FS && mop1t != OP_GS)
u->error= 1;
iop[0].type = UD_OP_REG;
iop[0].base = (mop1t - OP_ES) + UD_R_ES;
iop[0].size = 16;
break;
/* J */
case OP_J :
decode_imm(u, mop1s, &(iop[0]));
iop[0].type = UD_OP_JIMM;
break ;
/* PR, I */
case OP_PR:
if (MODRM_MOD(inp_peek(u)) != 3)
u->error = 1;
decode_modrm(u, &(iop[0]), mop1s, T_MMX, NULL, 0, T_NONE);
if (mop2t == OP_I)
decode_imm(u, mop2s, &(iop[1]));
break;
/* VR, I */
case OP_VR:
if (MODRM_MOD(inp_peek(u)) != 3)
u->error = 1;
decode_modrm(u, &(iop[0]), mop1s, T_XMM, NULL, 0, T_NONE);
if (mop2t == OP_I)
decode_imm(u, mop2s, &(iop[1]));
break;
/* P, Q[,I]/W/E[,I],VR */
case OP_P :
if (mop2t == OP_Q) {
decode_modrm(u, &(iop[1]), mop2s, T_MMX, &(iop[0]), mop1s, T_MMX);
if (mop3t == OP_I)
decode_imm(u, mop3s, &(iop[2]));
} else if (mop2t == OP_W) {
decode_modrm(u, &(iop[1]), mop2s, T_XMM, &(iop[0]), mop1s, T_MMX);
} else if (mop2t == OP_VR) {
if (MODRM_MOD(inp_peek(u)) != 3)
u->error = 1;
decode_modrm(u, &(iop[1]), mop2s, T_XMM, &(iop[0]), mop1s, T_MMX);
} else if (mop2t == OP_E) {
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_MMX);
if (mop3t == OP_I)
decode_imm(u, mop3s, &(iop[2]));
}
break;
/* R, C/D */
case OP_R :
if (mop2t == OP_C)
decode_modrm(u, &(iop[0]), mop1s, T_GPR, &(iop[1]), mop2s, T_CRG);
else if (mop2t == OP_D)
decode_modrm(u, &(iop[0]), mop1s, T_GPR, &(iop[1]), mop2s, T_DBG);
break;
/* C, R */
case OP_C :
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_CRG);
break;
/* D, R */
case OP_D :
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_DBG);
break;
/* Q, P */
case OP_Q :
decode_modrm(u, &(iop[0]), mop1s, T_MMX, &(iop[1]), mop2s, T_MMX);
break;
/* S, E */
case OP_S :
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_SEG);
break;
/* W, V */
case OP_W :
decode_modrm(u, &(iop[0]), mop1s, T_XMM, &(iop[1]), mop2s, T_XMM);
break;
/* V, W[,I]/Q/M/E */
case OP_V :
if (mop2t == OP_W) {
/* special cases for movlps and movhps */
if (MODRM_MOD(inp_peek(u)) == 3) {
if (u->mnemonic == UD_Imovlps)
u->mnemonic = UD_Imovhlps;
else
if (u->mnemonic == UD_Imovhps)
u->mnemonic = UD_Imovlhps;
}
decode_modrm(u, &(iop[1]), mop2s, T_XMM, &(iop[0]), mop1s, T_XMM);
if (mop3t == OP_I)
decode_imm(u, mop3s, &(iop[2]));
} else if (mop2t == OP_Q)
decode_modrm(u, &(iop[1]), mop2s, T_MMX, &(iop[0]), mop1s, T_XMM);
else if (mop2t == OP_M) {
if (MODRM_MOD(inp_peek(u)) == 3)
u->error= 1;
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_XMM);
} else if (mop2t == OP_E) {
decode_modrm(u, &(iop[1]), mop2s, T_GPR, &(iop[0]), mop1s, T_XMM);
} else if (mop2t == OP_PR) {
decode_modrm(u, &(iop[1]), mop2s, T_MMX, &(iop[0]), mop1s, T_XMM);
}
break;
/* DX, eAX/AL */
case OP_DX :
iop[0].type = UD_OP_REG;
iop[0].base = UD_R_DX;
iop[0].size = 16;
if (mop2t == OP_eAX) {
iop[1].type = UD_OP_REG;
iop[1].base = resolve_gpr32(u, mop2t);
} else if (mop2t == OP_AL) {
iop[1].type = UD_OP_REG;
iop[1].base = UD_R_AL;
iop[1].size = 8;
}
break;
/* I, I/AL/eAX */
case OP_I :
decode_imm(u, mop1s, &(iop[0]));
if (mop2t == OP_I)
decode_imm(u, mop2s, &(iop[1]));
else if (mop2t == OP_AL) {
iop[1].type = UD_OP_REG;
iop[1].base = UD_R_AL;
iop[1].size = 16;
} else if (mop2t == OP_eAX) {
iop[1].type = UD_OP_REG;
iop[1].base = resolve_gpr32(u, mop2t);
}
break;
/* O, AL/eAX */
case OP_O :
decode_o(u, mop1s, &(iop[0]));
iop[1].type = UD_OP_REG;
iop[1].size = (uint8_t)resolve_operand_size(u, mop1s);
if (mop2t == OP_AL)
iop[1].base = UD_R_AL;
else if (mop2t == OP_eAX)
iop[1].base = resolve_gpr32(u, mop2t);
else if (mop2t == OP_rAX)
iop[1].base = resolve_gpr64(u, mop2t);
break;
/* 3 */
case OP_I3 :
iop[0].type = UD_OP_CONST;
iop[0].lval.sbyte = 3;
break;
/* ST(n), ST(n) */
case OP_ST0 : case OP_ST1 : case OP_ST2 : case OP_ST3 :
case OP_ST4 : case OP_ST5 : case OP_ST6 : case OP_ST7 :
iop[0].type = UD_OP_REG;
iop[0].base = (mop1t-OP_ST0) + UD_R_ST0;
iop[0].size = 0;
if (mop2t >= OP_ST0 && mop2t <= OP_ST7) {
iop[1].type = UD_OP_REG;
iop[1].base = (mop2t-OP_ST0) + UD_R_ST0;
iop[1].size = 0;
}
break;
/* AX */
case OP_AX:
iop[0].type = UD_OP_REG;
iop[0].base = UD_R_AX;
iop[0].size = 16;
break;
/* none */
default :
iop[0].type = iop[1].type = iop[2].type = UD_NONE;
}
return 0;
}
/* -----------------------------------------------------------------------------
* decode_modrm() - Decodes ModRM Byte
* -----------------------------------------------------------------------------
*/
static void
decode_modrm(struct ud* u, struct ud_operand *op, unsigned int s,
unsigned char rm_type, struct ud_operand *opreg,
unsigned int reg_size, unsigned char reg_type)
{
unsigned char mod, rm, reg;
inp_next(u);
/* get mod, r/m and reg fields */
mod = MODRM_MOD(inp_curr(u));
rm = (REX_B(u->pfx_rex) << 3) | MODRM_RM(inp_curr(u));
reg = (REX_R(u->pfx_rex) << 3) | MODRM_REG(inp_curr(u));
op->size = (uint8_t) resolve_operand_size(u, s);
/* if mod is 11b, then the UD_R_m specifies a gpr/mmx/sse/control/debug */
if (mod == 3) {
op->type = UD_OP_REG;
if (rm_type == T_GPR)
op->base = decode_gpr(u, op->size, rm);
else op->base = resolve_reg(u, rm_type, (REX_B(u->pfx_rex) << 3) | (rm&7));
}
/* else its memory addressing */
else {
op->type = UD_OP_MEM;
/* 64bit addressing */
if (u->adr_mode == 64) {
op->base = UD_R_RAX + rm;
/* get offset type */
if (mod == 1)
op->offset = 8;
else if (mod == 2)
op->offset = 32;
else if (mod == 0 && (rm & 7) == 5) {
op->base = UD_R_RIP;
op->offset = 32;
} else op->offset = 0;
/* Scale-Index-Base (SIB) */
if ((rm & 7) == 4) {
inp_next(u);
op->scale = (1 << SIB_S(inp_curr(u))) & ~1;
op->index = UD_R_RAX + (SIB_I(inp_curr(u)) | (REX_X(u->pfx_rex) << 3));
op->base = UD_R_RAX + (SIB_B(inp_curr(u)) | (REX_B(u->pfx_rex) << 3));
/* special conditions for base reference */
if (op->index == UD_R_RSP) {
op->index = UD_NONE;
op->scale = UD_NONE;
}
if (op->base == UD_R_RBP || op->base == UD_R_R13) {
if (mod == 0)
op->base = UD_NONE;
if (mod == 1)
op->offset = 8;
else op->offset = 32;
}
}
}
/* 32-Bit addressing mode */
else if (u->adr_mode == 32) {
/* get base */
op->base = UD_R_EAX + rm;
/* get offset type */
if (mod == 1)
op->offset = 8;
else if (mod == 2)
op->offset = 32;
else if (mod == 0 && rm == 5) {
op->base = UD_NONE;
op->offset = 32;
} else op->offset = 0;
/* Scale-Index-Base (SIB) */
if ((rm & 7) == 4) {
inp_next(u);
op->scale = (1 << SIB_S(inp_curr(u))) & ~1;
op->index = UD_R_EAX + (SIB_I(inp_curr(u)) | (REX_X(u->pfx_rex) << 3));
op->base = UD_R_EAX + (SIB_B(inp_curr(u)) | (REX_B(u->pfx_rex) << 3));
if (op->index == UD_R_ESP) {
op->index = UD_NONE;
op->scale = UD_NONE;
}
/* special condition for base reference */
if (op->base == UD_R_EBP) {
if (mod == 0)
op->base = UD_NONE;
if (mod == 1)
op->offset = 8;
else op->offset = 32;
}
}
}
/* 16bit addressing mode */
else {
switch (rm) {
case 0: op->base = UD_R_BX; op->index = UD_R_SI; break;
case 1: op->base = UD_R_BX; op->index = UD_R_DI; break;
case 2: op->base = UD_R_BP; op->index = UD_R_SI; break;
case 3: op->base = UD_R_BP; op->index = UD_R_DI; break;
case 4: op->base = UD_R_SI; break;
case 5: op->base = UD_R_DI; break;
case 6: op->base = UD_R_BP; break;
case 7: op->base = UD_R_BX; break;
}
if (mod == 0 && rm == 6) {
op->offset= 16;
op->base = UD_NONE;
}
else if (mod == 1)
op->offset = 8;
else if (mod == 2)
op->offset = 16;
}
}
/* extract offset, if any */
switch(op->offset) {
case 8 : op->lval.ubyte = inp_uint8(u); break;
case 16: op->lval.uword = inp_uint16(u); break;
case 32: op->lval.udword = inp_uint32(u); break;
default: break;
}
/* resolve register encoded in reg field */
if (opreg) {
opreg->type = UD_OP_REG;
opreg->size = (uint8_t)resolve_operand_size(u, reg_size);
if (reg_type == T_GPR)
opreg->base = decode_gpr(u, opreg->size, reg);
else opreg->base = resolve_reg(u, reg_type, reg);
}
}
