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LibX86: Don't store the prefix/imm1/imm2 byte counts individually

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We can shrink and simplify Instruction a bit by combining these into
a single "extra bytes" count.
This commit is contained in:
Andreas Kling 2020-07-14 18:12:44 +02:00
parent 4f8e86ad67
commit bc66221ee3
1 changed files with 16 additions and 43 deletions
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59
Libraries/LibX86/Instruction.h
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@ -451,41 +451,15 @@ public:
return (rm() >> 3) & 7; return (rm() >> 3) & 7;
} }
u8 imm8() const u8 imm8() const { return m_imm1; }
{ u16 imm16() const { return m_imm1; }
ASSERT(m_imm1_bytes == 1); u32 imm32() const { return m_imm1; }
return m_imm1;
}
u16 imm16() const
{
ASSERT(m_imm1_bytes == 2);
return m_imm1;
}
u32 imm32() const
{
ASSERT(m_imm1_bytes == 4);
return m_imm1;
}
u8 imm8_1() const { return imm8(); } u8 imm8_1() const { return imm8(); }
u8 imm8_2() const u8 imm8_2() const { return m_imm2; }
{
ASSERT(m_imm2_bytes == 1);
return m_imm2;
}
u16 imm16_1() const { return imm16(); } u16 imm16_1() const { return imm16(); }
u16 imm16_2() const u16 imm16_2() const { return m_imm2; }
{
ASSERT(m_imm2_bytes == 2);
return m_imm2;
}
u32 imm32_1() const { return imm32(); } u32 imm32_1() const { return imm32(); }
u32 imm32_2() const u32 imm32_2() const { return m_imm2; }
{
ASSERT(m_imm2_bytes == 4);
return m_imm2;
}
u32 imm_address() const { return m_a32 ? imm32() : imm16(); } u32 imm_address() const { return m_a32 ? imm32() : imm16(); }
LogicalAddress imm_address16_16() const { return LogicalAddress(imm16_1(), imm16_2()); } LogicalAddress imm_address16_16() const { return LogicalAddress(imm16_1(), imm16_2()); }
@ -527,9 +501,7 @@ private:
bool m_has_sub_op { false }; bool m_has_sub_op { false };
bool m_has_rm { false }; bool m_has_rm { false };
unsigned m_imm1_bytes { 0 }; u8 m_extra_bytes { 0 };
unsigned m_imm2_bytes { 0 };
unsigned m_prefix_bytes { 0 };
Optional<SegmentRegister> m_segment_prefix; Optional<SegmentRegister> m_segment_prefix;
bool m_has_operand_size_override_prefix { false }; bool m_has_operand_size_override_prefix { false };
@ -805,9 +777,7 @@ ALWAYS_INLINE unsigned Instruction::length() const
++len; ++len;
len += m_modrm.m_displacement_bytes; len += m_modrm.m_displacement_bytes;
} }
len += m_imm1_bytes; len += m_extra_bytes;
len += m_imm2_bytes;
len += m_prefix_bytes;
return len; return len;
} }
@ -836,7 +806,8 @@ ALWAYS_INLINE Instruction::Instruction(InstructionStreamType& stream, bool o32,
: m_a32(a32) : m_a32(a32)
, m_o32(o32) , m_o32(o32)
{ {
for (;; ++m_prefix_bytes) { u8 prefix_bytes = 0;
for (;; ++prefix_bytes) {
u8 opbyte = stream.read8(); u8 opbyte = stream.read8();
if (opbyte == Prefix::OperandSizeOverride) { if (opbyte == Prefix::OperandSizeOverride) {
m_o32 = !o32; m_o32 = !o32;
@ -907,11 +878,11 @@ ALWAYS_INLINE Instruction::Instruction(InstructionStreamType& stream, bool o32,
return; return;
} }
m_imm1_bytes = m_descriptor->imm1_bytes_for_address_size(m_a32); auto imm1_bytes = m_descriptor->imm1_bytes_for_address_size(m_a32);
m_imm2_bytes = m_descriptor->imm2_bytes_for_address_size(m_a32); auto imm2_bytes = m_descriptor->imm2_bytes_for_address_size(m_a32);
// Consume immediates if present. // Consume immediates if present.
switch (m_imm2_bytes) { switch (imm2_bytes) {
case 1: case 1:
m_imm2 = stream.read8(); m_imm2 = stream.read8();
break; break;
@ -923,7 +894,7 @@ ALWAYS_INLINE Instruction::Instruction(InstructionStreamType& stream, bool o32,
break; break;
} }
switch (m_imm1_bytes) { switch (imm1_bytes) {
case 1: case 1:
m_imm1 = stream.read8(); m_imm1 = stream.read8();
break; break;
@ -935,6 +906,8 @@ ALWAYS_INLINE Instruction::Instruction(InstructionStreamType& stream, bool o32,
break; break;
} }
m_extra_bytes = prefix_bytes + imm1_bytes + imm2_bytes;
#ifdef DISALLOW_INVALID_LOCK_PREFIX #ifdef DISALLOW_INVALID_LOCK_PREFIX
if (m_has_lock_prefix && !m_descriptor->lock_prefix_allowed) { if (m_has_lock_prefix && !m_descriptor->lock_prefix_allowed) {
fprintf(stderr, "Instruction not allowed with LOCK prefix, this will raise #UD\n"); fprintf(stderr, "Instruction not allowed with LOCK prefix, this will raise #UD\n");