// see in assembly code are simple, but for the record:
//
// 1) Evaluation uses uint64; the old one used int64.
// 2) Precedence uses Go rules not C rules.

// expr = term | term ('+' | '-' | '|' | '^') term.
func (p *Parser) expr() uint64 {
	value := p.term()
	for {
		switch p.peek() {
		case '+':
			p.next()
			value += p.term()
		case '-':
			p.next()
			value -= p.term()

pkg encoding/hex, func AppendDecode([]uint8, []uint8) ([]uint8, error) #53693
pkg encoding/hex, func AppendEncode([]uint8, []uint8) []uint8 #53693
pkg go/ast, func NewPackage //deprecated #52463
pkg go/ast, func Unparen(Expr) Expr #60061
pkg go/ast, type Importer //deprecated #52463
pkg go/ast, type Object //deprecated #52463
pkg go/ast, type Package //deprecated #52463
pkg go/ast, type Scope //deprecated #52463

One of the integer part or the fractional part may be elided; one of the decimal point
or the exponent part may be elided.
An exponent value exp scales the mantissa (integer and fractional part) by 10<sup>exp</sup>.
</p>

<p>
A hexadecimal floating-point literal consists of a <code>0x</code> or <code>0X</code>

	MOVBU.W	-0x00ffffff(R2), R1  // MOVBU.W -16777215(R2), R1
	MOVB	R0, math·Exp(SB)     // MOVB R0, math.Exp(SB)
	MOVB	math·Exp(SB), R0     // MOVB math.Exp(SB), R0
	MOVBS	R0, math·Exp(SB)     // MOVBS R0, math.Exp(SB)
	MOVBS	math·Exp(SB), R0     // MOVBS math.Exp(SB), R0
	MOVBU	R0, math·Exp(SB)     // MOVBU R0, math.Exp(SB)
	MOVBU	math·Exp(SB), R0     // MOVBU math.Exp(SB), R0
	MOVB	R2, R0>>28(R1)                                    // 202ec1e7

One of the integer part or the fractional part may be elided; one of the decimal point
or the exponent part may be elided.
An exponent value exp scales the mantissa (integer and fractional part) by 10<sup>exp</sup>.
</p>

<p>
A hexadecimal floating-point literal consists of a <code>0x</code> or <code>0X</code>