65 lines
1.7 KiB
Go
65 lines
1.7 KiB
Go
package operand
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import (
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"fmt"
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"strconv"
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"strings"
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)
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// Constant represents a constant literal.
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type Constant interface {
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Op
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Bytes() int
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constant()
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}
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//go:generate go run make_const.go -output zconst.go
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// Special cases for floating point string representation.
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//
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// Issue 387 pointed out that floating point values that happen to be integers
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// need to have a decimal point to be parsed correctly.
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// String returns a representation the 32-bit float which is guaranteed to be
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// parsed as a floating point constant by the Go assembler.
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func (f F32) String() string { return asmfloat(float64(f), 32) }
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// String returns a representation the 64-bit float which is guaranteed to be
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// parsed as a floating point constant by the Go assembler.
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func (f F64) String() string { return asmfloat(float64(f), 64) }
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// asmfloat represents x as a string such that the assembler scanner will always
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// recognize it as a float. Specifically, ensure that when x is an integral
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// value, the result will still have a decimal point.
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func asmfloat(x float64, bits int) string {
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s := strconv.FormatFloat(x, 'f', -1, bits)
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if !strings.ContainsRune(s, '.') {
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s += ".0"
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}
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return s
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}
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// String is a string constant.
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type String string
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// Asm returns an assembly syntax representation of the string s.
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func (s String) Asm() string { return fmt.Sprintf("$%q", s) }
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// Bytes returns the length of s.
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func (s String) Bytes() int { return len(s) }
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func (s String) constant() {}
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// Imm returns an unsigned integer constant with size guessed from x.
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func Imm(x uint64) Constant {
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switch {
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case uint64(uint8(x)) == x:
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return U8(x)
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case uint64(uint16(x)) == x:
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return U16(x)
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case uint64(uint32(x)) == x:
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return U32(x)
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}
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return U64(x)
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}
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