LIR

  • Revision slug: Nanojit/LIR
  • Revision title: LIR
  • Revision id: 100602
  • Created:
  • Creator: Jorend
  • Is current revision? No
  • Comment 13 words removed

Revision Content

In Nanojit, LIR is the source language for compilation to machine code. LIR stands for low-level intermediate representation.

The LIR instruction set

Types in LIR. Values in LIR have a type: either 32-bit or 64-bit. A 32-bit value, additionally, may be a condition or not. Each instruction requires operands of a specific type and produces a result of a specific type.

LIR makes no distinction at all between pointers and integers of the same size, between signed and unsigned integer values, or between 64-bit floating-point and 64-bit integer values. It is acceptable to load a 64-bit value from memory using ldq and then use the result with a floating-point arithmetic operation such as fadd.

The names of the operands and results below indicate the types required by LIR. Names starting with i indicate 32-bit values. Results starting with b are 32-bit integers and additionally are conditions. Operand names starting with b must be conditions. Names starting with q or f indicate 64-bit values. (f and q indicate the same type as far as LIR is concerned, but f is used here for floating-point operations.) Operand names starting with p must be pointer-sized integers. That is, they must be 64 bits on a 64-bit platform and 32 bits otherwise.

Constants

The result of each of these instructions is a constant value.

On 32-bit platforms, int is used to load constant addresses; on 64-bit platforms, quad is used.  The convenience function LirWriter::insImmPtr() emits the appropriate instruction depending on the platform.

Note: These instructions are currently rendered in VerboseWriter output as lines containing only the symbolic name of the immediate value being loaded. The instruction name and numeric value are not displayed for short and int instructions. This is arguably a bug.

short

An immediate 32-bit integer that fits in a signed 16-bit integer.

i = short <number>

<number> must be an integer that fits in the range of a signed 16-bit integer (-32768 to 32767). The result of a short instruction is a 32-bit integer with the same value (sign-extended).

The result is a 32-bit integer. This is exactly like int but saves a few bytes in the LirBuffer.

int

An immediate 32-bit value.

i = int <number>

<number> must be an integer that fits in int32_t or uint32_t.

quad

An immediate 64-bit value.

q = quad <number>

<number> must be either an integer that fits in a signed or unsigned 64-bit integer; or a floating-point number (containing a decimal point).

Integer arithmetic

neg

32-bit integer negation.

i = neg i1

add

32-bit integer addition.

i = add i1, i2

qiadd

64-bit integer addition.

q = qiadd q1, q2

sub

32-bit integer subtraction.

i = sub i1, i2

mul

32-bit integer multiplication.

i = mul i1, i2

and

32-bit bitwise AND.

i = and i1, i2

qiand

64-bit bitwise AND.

q = qiand q1, q2

or

32-bit bitwise OR.

i = or i1, i2

qior

64-bit bitwise OR.

q = qior q1, q2

xor

32-bit bitwise XOR.

i = or i1, i2

not

32-bit bitwise NOT.

i = not i1

lsh

32-bit left shift.

i = lsh i1, i2

qilsh

64-bit left shift.

q = qilsh q1, q2

rsh

32-bit right shift with sign extend.

i = rsh i1, i2

ush

32-bit unsigned right shift.

i = ush i1, i2

The most significant bit of the result value is 0.

Floating-point arithmetic

Any 64-bit value may be treated as a floating-point number. These operations behave according to the rules of IEEE 754 double-precision arithmetic. Some details may be found in the ECMAScript language standard, {{ Es3_spec("11.5.1") }} and subsequent sections.

fneg

Floating-point negation.

f = fneg f1

fadd

Floating-point addition.

f = fadd f1, f2

fsub

Floating-point subtraction.

f = fsub f1, f2

fmul

Floating-point multiplication.

f = mul f1, f2

fdiv

Floating-point division.

f = div f1, f2

 

 

Numeric conversions

qlo

Get the low 32 bits of a 64-bit value.

i = qlo q

qhi

Get the high 32 bits of a 64-bit value.

i = qhi q

qjoin

Join two 32-bit values to form a 64-bit value.

q = qjoin i1, i2

i2f

Convert signed 32-bit integer to floating-point number.

f = i2f i1

u2f

Convert unsigned 32-bit integer to floating-point number.

f = u2f i1

Loads and stores

LIR provides a single addressing mode.  Each load or store instruction takes a pointer provided by a previous instruction and a constant offset (in bytes). The offset must fit in the range of a signed 32-bit integer, even on 64-bit platforms.

Although the ld instruction takes 2 operands, a pointer and offset, the second operand must be the result of an int instruction.  This is enforced with assertions.

The convenience functions LirWriter::insLoad(LOpcode op, LIns *base, int32_t offset) and LirWriter::insStorei(LIns *value, LIns *base, int32_t offset) should be used to emit loads and stores.

ld

32-bit load. This instruction is never removed by common subexpression elimination.

i = ld p1[offset]

ldq

64-bit load. This instruction is never removed by common subexpression elimination.

q = ldq p1[offset]

ldcb

8-bit load. This instruction may be removed by common subexpression elimination.

i = ldcb p1[offset]

ldcs

16-bit load. This instruction may be removed by common subexpression elimination.

i = ldcs p1[offset]

ldc

32-bit load. This instruction may be removed by common subexpression elimination.

i = ldc p1[offset]

ldqc

64-bit load. This instruction may be removed by common subexpression elimination.

q = ldqc p1[offset]

st

32-bit store.

st p1[offset] = i2

stq

64-bit store.

stq p1[offset] = q2

offset must fit in the range of a 32-bit integer, even on 64-bit platforms.

sti

32-bit store.

sti p1[offset] = i2

offset must be in the range [-128, 127]. sti is identical to the corresponding st instruction but takes a few bytes less to represent in a LirBuffer.

stqi

64-bit store.

stqi p1[offset] = q2

offset must be in the range [-128, 127]. sti is identical to the corresponding st instruction but takes a few bytes less to represent in a LirBuffer.

Subroutine calls

calli

Indirect subroutine call returning a 32-bit integer value.

call

Subroutine call returning a 32-bit integer value.

callh

fcalli

Indirect subroutine call returning a 64-bit value.

fcall

Subroutine call returning a 64-bit value.

ret

fret

Conditions

The result of these instructions is a 32-bit value, either 1 (true) or 0 (false). Conditions are used as operands to conditional branch, guard, and conditional move instructions.

eq

32-bit integer equality test.

b = eq i1, i2

There is no not-equal instruction. Instead, flip the instruction that uses the result, or add a not instruction.

lt

Signed 32-bit integer less-than test.

b = lt i1, i2

gt

Signed 32-bit integer greater-than test.

b = gt i1, i2

le

Signed 32-bit integer less-than-or-equals test.

b = le i1, i2

ge

Signed 32-bit integer greater-than-or-equals test.

b = ge i1, i2

ult

Unsigned 32-bit integer less-than test.

b = ult i1, i2

ugt

Unsigned 32-bit integer greater-than test.

b = ugt i1, i2

ule

Unsigned 32-bit integer less-than-or-equals test.

b = ule i1, i2

uge

Unsigned 32-bit integer greater-than-or-equals test.

b = uge i1, i2

feq

Floating-point equality test.

b = feq f1, f2

flt

Floating-point less-than test.

b = flt f1, f2

fgt

Floating-point greater-than test.

b = fgt f1, f2

fle

Floating-point less-than-or-equals test.

b = fle f1, f2

fge

Floating-point greater-than-or-equals test.

b = fge f1, f2

ov

Test for overflow.

b = ov i1

The result is 1 if i1 is the result of an add, sub, or neg that overflowed the range of a signed 32-bit integer, for example.

Note: nanojit may produce incorrect code if this instruction does not immediately follow the instruction that produced i1. On Intel, this reads the overflow condition flag. Other platforms have to emulate this behavior.

cs

Test for carry.

b = cs i1

The result is 1 if i1 is the result of an add that overflowed the range of an unsigned 32-bit integer, for example.

Note: nanojit may produce incorrect code if this instruction does not immediately follow the instruction that produced i1. On Intel, this reads the carry condition flag. Other platforms have to emulate this behavior.

Branches

loop

Loop fragment.

x

Exit unconditionally.

xt

Exit if true.

xf

Exit if false.

xbarrier

Do not exit but emit writes to flush all values to the stack.

j

Jump unconditionally.

jt

Jump if true.

jf

Jump if false.

label

A jump target.

ji

Indirect jump.

Conditional moves

Note: These two instructions can be written using the idiom lirwriter->ins2(LIR_cmov, b1, lirwriter->ins2(LIR_2, i2, i3)). The LIR_2 instruction serves only to group the second and third operands, since LirWriter has no ins3 method.

The LirWriter::ins_choose() convenience method can be used instead. It uses the above idiom.

cmov

Choice of two 32-bit values.

i = cmov b1, i2, i3

qcmov

Choice of two 64-bit values.

Note: This instruction currently does not work on 32-bit Intel platforms.

q = qcmov b1, q2, q3

Special operations

start

nearskip

skip

neartramp

tramp

Operations that are weird but don't count as special

addp

param

file

line

alloc

Allocate stack space, as though with the C standard library function alloca.

p = alloc size

size must be a multiple of 4 that does not exceed 262140 (0xffff << 2).

live

Extend live range of reference.

Revision Source

<p>In Nanojit, <strong>LIR</strong> is the source language for compilation to machine code. LIR stands for <em>low-level intermediate representation</em>.</p>
<h2>The LIR instruction set</h2>
<p><strong>Types in LIR.</strong> Values in LIR have a type: either 32-bit or 64-bit. A 32-bit value, additionally, may be a condition or not. Each instruction requires operands of a specific type and produces a result of a specific type.</p>
<p>LIR makes no distinction at all between pointers and integers of the same size, between signed and unsigned integer values, or between 64-bit floating-point and 64-bit integer values. It is acceptable to load a 64-bit value from memory using <code>ldq</code> and then use the result with a floating-point arithmetic operation such as <code>fadd</code>.</p>
<p>The names of the operands and results below indicate the types required by LIR. Names starting with <em>i</em> indicate 32-bit values. Results starting with <em>b</em> are 32-bit integers and additionally are conditions. Operand names starting with <em>b</em> must be conditions. Names starting with <em>q</em> or <em>f</em> indicate 64-bit values. (<em>f</em> and <em>q</em> indicate the same type as far as LIR is concerned, but <em>f</em> is used here for floating-point operations.) Operand names starting with <em>p</em> must be pointer-sized integers. That is, they must be 64 bits on a 64-bit platform and 32 bits otherwise.</p>
<h3>Constants</h3>
<p>The result of each of these instructions is a constant value.</p>
<p>On 32-bit platforms, <code>int</code> is used to load constant addresses; on 64-bit platforms, <code>quad</code> is used.  The convenience function <code>LirWriter::insImmPtr()</code> emits the appropriate instruction depending on the platform.</p>
<p>Note: These instructions are currently rendered in <code>VerboseWriter</code> output as lines containing only the symbolic name of the immediate value being loaded. The instruction name and numeric value are not displayed for <code>short</code> and <code>int</code> instructions. This is arguably a bug.</p>
<h4>short</h4>
<p>An immediate 32-bit integer that fits in a signed 16-bit integer.</p>
<pre><var>i</var> = short <var>&lt;number&gt;</var></pre>
<p><code><var>&lt;number&gt;</var></code> must be an integer that fits in the range of a signed 16-bit integer (-32768 to 32767). The result of a <code>short</code> instruction is a 32-bit integer with the same value (sign-extended).</p>
<p>The result is a 32-bit integer. This is exactly like <code>int</code> but saves a few bytes in the <code>LirBuffer</code>.</p>
<h4>int</h4>
<p>An immediate 32-bit value.</p>
<pre><var>i</var> = int <var>&lt;number&gt;</var></pre>
<p><code><var>&lt;number&gt;</var></code> must be an integer that fits in <code>int32_t</code> or <code>uint32_t</code>.</p>
<h4>quad</h4>
<p>An immediate 64-bit value.</p>
<pre><var>q</var> = quad <var>&lt;number&gt;</var></pre>
<p><code><var>&lt;number&gt;</var></code> must be either an integer that fits in a signed or unsigned 64-bit integer; or a floating-point number (containing a decimal point).</p><h3>Integer arithmetic</h3>
<h4>neg</h4>
<p>32-bit integer negation.</p>
<pre><var>i</var> = neg <var>i1</var></pre>
<h4>add</h4>
<p>32-bit integer addition.</p>
<pre><var>i</var> = add <var>i1</var>, <var>i2</var></pre>
<h4>qiadd</h4>
<p>64-bit integer addition.</p>
<pre><var>q</var> = qiadd <var>q1</var>, <var>q2</var></pre>
<h4>sub</h4>
<p>32-bit integer subtraction.</p>
<pre><var>i</var> = sub <var>i1</var>, <var>i2</var></pre>
<h4>mul</h4>
<p>32-bit integer multiplication.</p>
<pre><var>i</var> = mul <var>i1</var>, <var>i2</var></pre>
<h4>and</h4>
<p>32-bit bitwise AND.</p>
<pre><var>i</var> = and <var>i1</var>, <var>i2</var></pre>
<h4>qiand</h4>
<p>64-bit bitwise AND.</p>
<pre><var>q</var> = qiand <var>q1</var>, <var>q2</var></pre>
<h4>or</h4>
<p>32-bit bitwise OR.</p>
<pre><var>i</var> = or <var>i1</var>, <var>i2</var></pre>
<h4>qior</h4>
<p>64-bit bitwise OR.</p>
<pre><var>q</var> = qior <var>q1</var>, <var>q2</var></pre>
<h4>xor</h4>
<p>32-bit bitwise XOR.</p>
<pre><var>i</var> = or <var>i1</var>, <var>i2</var></pre>
<h4>not</h4>
<p>32-bit bitwise NOT.</p>
<pre><var>i</var> = not <var>i1</var></pre>
<h4>lsh</h4>
<p>32-bit left shift.</p>
<pre><var>i</var> = lsh <var>i1</var>, <var>i2</var></pre>
<h4>qilsh</h4>
<p>64-bit left shift.</p>
<pre><var>q</var> = qilsh <var>q1</var>, <var>q2</var></pre>
<h4>rsh</h4>
<p>32-bit right shift with sign extend.</p>
<pre><var>i</var> = rsh <var>i1</var>, <var>i2</var>
</pre><h4>ush</h4>
<p>32-bit unsigned right shift.</p>
<pre><var>i</var> = ush <var>i1</var>, <var>i2</var></pre>
<p>The most significant bit of the result value is 0.</p>
<h3>Floating-point arithmetic</h3>
<p>Any 64-bit value may be treated as a floating-point number. These operations behave according to the rules of IEEE 754 double-precision arithmetic. Some details may be found in the ECMAScript language standard, {{ Es3_spec("11.5.1") }} and subsequent sections.</p>
<h4>fneg</h4>
<p>Floating-point negation.</p>
<pre><var>f</var> = fneg <var>f1</var></pre>
<h4>fadd</h4>
<p>Floating-point addition.</p>
<pre><var>f</var> = fadd <var>f1</var>, <var>f2</var></pre>
<h4>fsub</h4>
<p>Floating-point subtraction.</p>
<pre><var>f</var> = fsub <var>f1</var>, <var>f2</var></pre>
<h4>fmul</h4>
<p>Floating-point multiplication.</p>
<pre><var>f</var> = mul <var>f1</var>, <var>f2</var></pre>
<h4>fdiv</h4>
<p>Floating-point division.</p>
<pre><var>f</var> = div <var>f1</var>, <var>f2</var></pre>
<p> </p>
<p> </p><h3>Numeric conversions</h3>
<h4>qlo</h4>
<p>Get the low 32 bits of a 64-bit value.</p>
<pre><var>i</var> = qlo <var>q</var></pre>
<h4>qhi</h4>
<p>Get the high 32 bits of a 64-bit value.</p>
<pre><var>i</var> = qhi <var>q</var></pre>
<h4>qjoin</h4>
<p>Join two 32-bit values to form a 64-bit value.</p>
<pre><var>q</var> = qjoin <var>i1</var>, <var>i2</var></pre>
<h4>i2f</h4>
<p>Convert signed 32-bit integer to floating-point number.</p>
<pre><var>f</var> = i2f <var>i1</var></pre>
<h4>u2f</h4>
<p>Convert unsigned 32-bit integer to floating-point number.</p>
<pre><var>f</var> = u2f <var>i1</var></pre>
<h3>Loads and stores</h3>
<p>LIR provides a single addressing mode.  Each load or store instruction takes a pointer provided by a previous instruction and a constant offset (in bytes). The <code><var>offset</var></code> must fit in the range of a signed 32-bit integer, even on 64-bit platforms.</p>
<p>Although the <code>ld</code> instruction takes 2 operands, a pointer and offset, the second operand must be the result of an <code>int</code> instruction.  This is enforced with assertions.</p>
<p>The convenience functions <code>LirWriter::insLoad(LOpcode op, LIns *base, int32_t offset)</code> and <code>LirWriter::insStorei(LIns *value, LIns *base, int32_t offset)</code> should be used to emit loads and stores.</p>
<h4>ld</h4>
<p>32-bit load. This instruction is never removed by common subexpression elimination.</p>
<pre><var>i</var> = ld <var>p1</var>[<em>offset</em>]</pre>
<h4>ldq</h4>
<p>64-bit load. This instruction is never removed by common subexpression elimination.</p>
<pre><var>q</var> = ldq <var>p1</var>[<var>offset</var>]</pre>
<h4>ldcb</h4>
<p>8-bit load. This instruction may be removed by common subexpression elimination.</p>
<pre><var>i</var> = ldcb <var>p1</var>[<var>offset</var>]</pre>
<h4>ldcs</h4>
<p>16-bit load. This instruction may be removed by common subexpression elimination.</p>
<pre><var>i</var> = ldcs <var>p1</var>[<var>offset</var>]</pre>
<h4>ldc</h4>
<p>32-bit load. This instruction may be removed by common subexpression elimination.</p>
<pre><var>i</var> = ldc <var>p1</var>[<var>offset</var>]</pre>
<h4>ldqc</h4>
<p>64-bit load. This instruction may be removed by common subexpression elimination.</p>
<pre><var>q</var> = ldqc <var>p1</var>[<var>offset</var>]</pre>
<h4>st</h4>
<p>32-bit store.</p>
<pre>st <var>p1</var>[<var>offset</var>] = <var>i2</var><code><var><br></var></code></pre>
<h4>stq</h4>
<p>64-bit store.</p>
<pre>stq <var>p1</var>[<var>offset</var>] = <var>q2</var></pre>
<p><code><var>offset</var></code> must fit in the range of a 32-bit integer, even on 64-bit platforms.</p>
<h4>sti</h4>
<p>32-bit store.</p>
<pre>sti <var>p1</var>[<var>offset</var>] = <var>i2</var></pre>
<p><code><var>offset</var></code> must be in the range [-128, 127]. <code>sti</code> is identical to the corresponding <code>st</code> instruction but takes a few bytes less to represent in a <code>LirBuffer</code>.</p>
<h4>stqi</h4>
<p>64-bit store.</p>
<pre>stqi <var>p1</var>[<var>offset</var>] = <var>q2</var></pre>
<p><code><var>offset</var></code> must be in the range [-128, 127]. <code>sti</code> is identical to the corresponding <code>st</code> instruction but takes a few bytes less to represent in a <code>LirBuffer</code>.</p><h3>Subroutine calls</h3>
<h4>calli</h4>
<p>Indirect subroutine call returning a 32-bit integer value.</p>
<h4>call</h4>
<p>Subroutine call returning a 32-bit integer value.</p>
<h4>callh</h4>
<h4>fcalli</h4>
<p>Indirect subroutine call returning a 64-bit value.</p>
<h4>fcall</h4>
<p>Subroutine call returning a 64-bit value.</p>
<h4>ret</h4>
<h4>fret</h4>
<h3>Conditions</h3>
<p>The result of these instructions is a 32-bit value, either 1 (true) or 0 (false). Conditions are used as operands to conditional branch, guard, and conditional move instructions.</p>
<h4>eq</h4>
<p>32-bit integer equality test.</p>
<pre><var>b</var> = eq <var>i1</var>, <var>i2</var></pre>
<p>There is no not-equal instruction. Instead, flip the instruction that uses the result, or add a <code>not</code> instruction.</p>
<h4>lt</h4>
<p>Signed 32-bit integer less-than test.</p>
<pre><var>b</var> = lt <var>i1</var>, <var>i2</var></pre>
<h4>gt</h4>
<p>Signed 32-bit integer greater-than test.</p>
<pre><var>b</var> = gt <var>i1</var>, <var>i2</var></pre>
<h4>le</h4>
<p>Signed 32-bit integer less-than-or-equals test.</p>
<pre><var>b</var> = le <var>i1</var>, <var>i2</var></pre>
<h4>ge</h4>
<p>Signed 32-bit integer greater-than-or-equals test.</p>
<pre><var>b</var> = ge <var>i1</var>, <var>i2</var></pre>
<h4>ult</h4>
<p>Unsigned 32-bit integer less-than test.</p>
<pre><var>b</var> = ult <var>i1</var>, <var>i2</var></pre>
<h4>ugt</h4>
<p>Unsigned 32-bit integer greater-than test.</p>
<pre><var>b</var> = ugt <var>i1</var>, <var>i2</var></pre>
<h4>ule</h4>
<p>Unsigned 32-bit integer less-than-or-equals test.</p>
<pre><var>b</var> = ule <var>i1</var>, <var>i2</var></pre>
<h4>uge</h4>
<p>Unsigned 32-bit integer greater-than-or-equals test.</p>
<pre><var>b</var> = uge <var>i1</var>, <var>i2</var></pre>
<h4>feq</h4>
<p>Floating-point equality test.</p>
<pre><var>b</var> = feq <var>f1</var>, <var>f2</var></pre>
<h4>flt</h4>
<p>Floating-point less-than test.</p>
<pre><var>b</var> = flt <var>f1</var>, <var>f2</var></pre>
<h4>fgt</h4>
<p>Floating-point greater-than test.</p>
<pre><var>b</var> = fgt <var>f1</var>, <var>f2</var></pre>
<h4>fle</h4>
<p>Floating-point less-than-or-equals test.</p>
<pre><var>b</var> = fle <var>f1</var>, <var>f2</var></pre>
<h4>fge</h4>
<p>Floating-point greater-than-or-equals test.</p>
<pre><var>b</var> = fge <var>f1</var>, <var>f2</var></pre>
<h4>ov</h4>
<p>Test for overflow.</p>
<pre><var>b</var> = ov <var>i1</var></pre>
<p>The result is <code>1</code> if <code><var>i1</var></code> is the result of an <code>add</code>, <code>sub</code>, or <code>neg</code> that overflowed the range of a signed 32-bit integer, for example.</p>
<p>Note: nanojit may produce incorrect code if this instruction does not immediately follow the instruction that produced <code><var>i1</var></code>. On Intel, this reads the overflow condition flag. Other platforms have to emulate this behavior.</p>
<h4>cs</h4>
<p>Test for carry.</p>
<pre><var>b</var> = cs <var>i1</var></pre>
<p>The result is <code>1</code> if <code><var>i1</var></code> is the result of an <code>add</code> that overflowed the range of an unsigned 32-bit integer, for example.</p>
<p>Note: nanojit may produce incorrect code if this instruction does not immediately follow the instruction that produced <code><var>i1</var></code>. On Intel, this reads the carry condition flag. Other platforms have to emulate this behavior.</p><h3>Branches</h3>
<h4>loop</h4>
<p>Loop fragment.</p>
<h4>x</h4>
<p>Exit unconditionally.</p>
<h4>xt</h4>
<p>Exit if true.</p>
<h4>xf</h4>
<p>Exit if false.</p>
<h4>xbarrier</h4>
<p>Do not exit but emit writes to flush all values to the stack.</p>
<h4>j</h4>
<p>Jump unconditionally.</p>
<h4>jt</h4>
<p>Jump if true.</p>
<h4>jf</h4>
<p>Jump if false.</p>
<h4>label</h4>
<p>A jump target.</p>
<h4>ji</h4>
<p>Indirect jump.</p>
<h3>Conditional moves</h3>
<p>Note: These two instructions can be written using the idiom <code>lirwriter-&gt;ins2(LIR_cmov, b1, lirwriter-&gt;ins2(LIR_2, i2, i3))</code>. The <code>LIR_2</code> instruction serves only to group the second and third operands, since <code>LirWriter</code> has no <code>ins3</code> method.</p>
<p>The <code>LirWriter::ins_choose()</code> convenience method can be used instead. It uses the above idiom.</p>
<h4>cmov</h4>
<p>Choice of two 32-bit values.</p>
<pre><var>i</var> = cmov <var>b1</var>, <var>i2</var>, <var>i3</var></pre>
<h4>qcmov</h4>
<p>Choice of two 64-bit values.</p>
<p>Note: This instruction currently does not work on 32-bit Intel platforms.</p>
<pre><var>q</var> = qcmov <var>b1</var>, <var>q2</var>, <var>q3</var></pre>
<h3>Special operations</h3>
<h4>start</h4>
<h4>nearskip</h4>
<h4>skip</h4>
<h4>neartramp</h4>
<h4>tramp</h4>
<h3>Operations that are weird but don't count as special</h3>
<h4>addp</h4>
<h4>param</h4>
<h4>file</h4>
<h4>line</h4>
<h4>alloc</h4>
<p>Allocate stack space, as though with the C standard library function <code>alloca</code>.</p>
<pre><var>p</var> = alloc <var>size</var></pre>
<p><code><var>size</var></code> must be a multiple of 4 that does not exceed 262140 (<code>0xffff &lt;&lt; 2</code>).</p><h4>live</h4>
<p>Extend live range of reference.</p>
Revert to this revision