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Slightly improve string instructions

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This commit is contained in:
Fabian 2020-12-31 19:14:31 -06:00
parent 3b9bb1049e
commit 4c61535b12
3 changed files with 78 additions and 54 deletions
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15
src/rust/cpu2/cpu.rs
View file

@ -3249,22 +3249,13 @@ pub unsafe fn get_reg_asize(reg: i32) -> i32 {
};
}
pub unsafe fn set_ecx_asize(is_asize_32: bool, value: i32) {
if is_asize_32 {
*reg32.offset(ECX as isize) = value
}
else {
*reg16.offset(CX as isize) = value as u16
};
}
pub unsafe fn add_reg_asize(is_asize_32: bool, reg: i32, value: i32) {
pub unsafe fn set_reg_asize(is_asize_32: bool, reg: i32, value: i32) {
dbg_assert!(reg == ECX || reg == ESI || reg == EDI);
if is_asize_32 {
*reg32.offset(reg as isize) += value;
*reg32.offset(reg as isize) = value
}
else {
*reg16.offset((reg << 1) as isize) += value as u16;
*reg16.offset((reg << 1) as isize) = value as u16
};
}

108
src/rust/cpu2/string.rs
View file

@ -118,6 +118,38 @@ unsafe fn string_instruction(
Size::D => -1,
};
let increment = direction * size_bytes;
let data = match instruction {
Instruction::Stos | Instruction::Scas => *reg32.offset(EAX as isize),
_ => 0,
};
let mut src = match instruction {
Instruction::Movs | Instruction::Cmps | Instruction::Lods | Instruction::Outs => {
read_reg32(ESI) & asize_mask
},
_ => 0,
};
let mut dst = match instruction {
Instruction::Movs
| Instruction::Cmps
| Instruction::Stos
| Instruction::Scas
| Instruction::Ins => read_reg32(EDI) & asize_mask,
_ => 0,
};
let mut count = match rep {
Rep::Z | Rep::NZ => {
let c = read_reg32(ECX) & asize_mask;
if c == 0 {
return;
};
c
},
Rep::None => 0,
};
let port = match instruction {
Instruction::Ins | Instruction::Outs => {
let port = *reg16.offset(DX as isize) as i32;
@ -129,47 +161,17 @@ unsafe fn string_instruction(
_ => 0,
};
let data = match instruction {
Instruction::Stos | Instruction::Scas => *reg32.offset(EAX as isize),
_ => 0,
};
loop {
let count = match rep {
Rep::Z | Rep::NZ => {
let c = read_reg32(ECX) & asize_mask;
if c == 0 {
return;
};
c
},
Rep::None => 0,
};
let src = match instruction {
Instruction::Movs | Instruction::Cmps | Instruction::Lods | Instruction::Outs => {
read_reg32(ESI) & asize_mask
},
_ => 0,
};
let dst = match instruction {
Instruction::Movs
| Instruction::Cmps
| Instruction::Stos
| Instruction::Scas
| Instruction::Ins => read_reg32(EDI) & asize_mask,
_ => 0,
};
match instruction {
Instruction::Ins => {
// check fault *before* reading from port
return_on_pagefault!(writable_or_pagefault(es + dst, size_bytes));
break_on_pagefault!(writable_or_pagefault(es + dst, size_bytes));
},
_ => {},
};
let src_val = match instruction {
Instruction::Movs | Instruction::Cmps | Instruction::Lods | Instruction::Outs => {
return_on_pagefault!(match size {
break_on_pagefault!(match size {
Size::B => safe_read8(ds + src),
Size::W => safe_read16(ds + src),
Size::D => safe_read32s(ds + src),
@ -185,9 +187,9 @@ unsafe fn string_instruction(
match instruction {
Instruction::Cmps | Instruction::Scas => match size {
Size::B => cmp8(src_val, return_on_pagefault!(safe_read8(es + dst))),
Size::W => cmp16(src_val, return_on_pagefault!(safe_read16(es + dst))),
Size::D => cmp32(src_val, return_on_pagefault!(safe_read32s(es + dst))),
Size::B => cmp8(src_val, break_on_pagefault!(safe_read8(es + dst))),
Size::W => cmp16(src_val, break_on_pagefault!(safe_read16(es + dst))),
Size::D => cmp32(src_val, break_on_pagefault!(safe_read32s(es + dst))),
},
Instruction::Outs => match size {
Size::B => io_port_write8(port, src_val),
@ -200,9 +202,9 @@ unsafe fn string_instruction(
Size::D => *reg32.offset(EAX as isize) = src_val,
},
Instruction::Movs | Instruction::Stos | Instruction::Ins => match size {
Size::B => return_on_pagefault!(safe_write8(es + dst, src_val)),
Size::W => return_on_pagefault!(safe_write16(es + dst, src_val)),
Size::D => return_on_pagefault!(safe_write32(es + dst, src_val)),
Size::B => break_on_pagefault!(safe_write8(es + dst, src_val)),
Size::W => break_on_pagefault!(safe_write16(es + dst, src_val)),
Size::D => break_on_pagefault!(safe_write32(es + dst, src_val)),
},
};
@ -211,12 +213,12 @@ unsafe fn string_instruction(
| Instruction::Cmps
| Instruction::Stos
| Instruction::Scas
| Instruction::Ins => add_reg_asize(is_asize_32, EDI, direction * size_bytes),
| Instruction::Ins => dst = dst + increment & asize_mask,
_ => {},
}
match instruction {
Instruction::Movs | Instruction::Cmps | Instruction::Lods | Instruction::Outs => {
add_reg_asize(is_asize_32, ESI, direction * size_bytes)
src = src + increment & asize_mask
},
_ => {},
};
@ -228,8 +230,8 @@ unsafe fn string_instruction(
(Rep::NZ, Instruction::Scas | Instruction::Cmps) => !getzf(),
_ => true,
};
add_reg_asize(is_asize_32, ECX, -1);
if count != 1 && rep_cmp {
count -= 1;
if count != 0 && rep_cmp {
//*instruction_pointer = *previous_ip
}
else {
@ -241,6 +243,28 @@ unsafe fn string_instruction(
},
}
}
match instruction {
Instruction::Movs
| Instruction::Cmps
| Instruction::Stos
| Instruction::Scas
| Instruction::Ins => set_reg_asize(is_asize_32, EDI, dst),
_ => {},
}
match instruction {
Instruction::Movs | Instruction::Cmps | Instruction::Lods | Instruction::Outs => {
set_reg_asize(is_asize_32, ESI, src)
},
_ => {},
};
match rep {
Rep::Z | Rep::NZ => {
set_reg_asize(is_asize_32, ECX, count);
},
Rep::None => {},
}
}
#[no_mangle]

9
src/rust/paging.rs
View file

@ -14,3 +14,12 @@ macro_rules! return_on_pagefault {
}
};
}
macro_rules! break_on_pagefault {
($expr:expr) => {
match $expr {
Ok(v) => v,
Err(()) => break,
}
};
}