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Fix short jumps for 16bit x86.nz (#8220)

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FIX #8219
This commit is contained in:
Sven Steinbauer 2017-08-15 17:45:31 +01:00 committed by radare
parent 7cce899c63
commit 746eb01344
1 changed files with 18 additions and 37 deletions
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55
libr/asm/p/asm_x86_nz.c
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@ -1071,8 +1071,9 @@ static int opint(RAsm *a, ut8 *data, const Opcode *op) {
static int opjc(RAsm *a, ut8 *data, const Opcode *op) {
int l = 0;
bool is_short = op->is_short;
int immediate = op->operands[0].immediate * op->operands[0].sign;
if (op->is_short && (immediate > ST8_MAX || immediate < ST8_MIN)) {
if (is_short && (immediate > ST8_MAX || immediate < ST8_MIN)) {
return l;
}
immediate -= a->pc;
@ -1097,8 +1098,16 @@ static int opjc(RAsm *a, ut8 *data, const Opcode *op) {
}
return l;
}
if (immediate <= 0x81 && immediate > -0x7f) {
is_short = true;
}
if (a->bits == 16 && (immediate > 0x81 || immediate < -0x7e)) {
data[l++] = 0x66;
is_short = false;
immediate --;
}
if (!op->is_short) {data[l++] = 0x0f;}
if (!is_short) {data[l++] = 0x0f;}
if (!strcmp (op->mnemonic, "ja") ||
!strcmp (op->mnemonic, "jnbe")) {
data[l++] = 0x87;
@ -1147,13 +1156,13 @@ static int opjc(RAsm *a, ut8 *data, const Opcode *op) {
!strcmp (op->mnemonic, "jz")) {
data[l++] = 0x88;
}
if (op->is_short) {
if (is_short) {
data[l-1] -= 0x10;
}
immediate -= op->is_short ? 2 : 6;
immediate -= is_short ? 2 : 6;
data[l++] = immediate;
if (!op->is_short) {
if (!is_short) {
data[l++] = immediate >> 8;
data[l++] = immediate >> 16;
data[l++] = immediate >> 24;
@ -1741,6 +1750,10 @@ static int oploop(RAsm *a, ut8 *data, const Opcode *op) {
static int opret(RAsm *a, ut8 *data, const Opcode *op) {
int l = 0;
int immediate = 0;
if (a->bits == 16) {
data[l++] = 0xc3;
return l;
}
if (op->operands[0].type == OT_UNKNOWN) {
data[l++] = 0xc3;
} else if (op->operands[0].type & (OT_CONSTANT | OT_WORD)) {
@ -2622,44 +2635,12 @@ static ut64 getnum(RAsm *a, const char *s) {
return r_num_math (a->num, s);
}
static int assemble16(RAsm *a, RAsmOp *ao, const char *str) {
int l = 0;
ut8 *data = ao->buf;
if (!strcmp (str, "nop")) {
data[l++] = 0x90;
} else if (!strcmp (str, "ret")) {
data[l++] = 0xc3;
} else if (!strcmp (str, "int3")) {
data[l++] = 0xcc;
} else if (!strncmp (str, "xor al,", 7)) {
// just to make the test happy, this needs much more work
const char *comma = strchr (str, ',');
if (comma) {
int n = getnum (a, comma + 1);
data[l++] = 0x34;
data[l++] = n;
}
} else if (!strncmp (str, "jmp ", 4)) {
int n = getnum (a, str + 4);
if (n > 0x81) {
return -1;
}
data[l++] = 0xeb;
data[l++] = n - 2;
}
return l;
}
static int assemble(RAsm *a, RAsmOp *ao, const char *str) {
ut8 *data = ao->buf;
char op[128];
LookupTable *lt_ptr;
int retval;
if (a->bits == 16) {
return assemble16 (a, ao, str);
}
strncpy (op, str, sizeof (op) - 1);
op[sizeof (op) - 1] = '\0';