0d789c8353
Issue #387 pointed out that integer float data is printed incorrectly, such that it is not parsed correctly by the Go assembler. Specifically, integer values need the decimal point, otherwise they will be treated as integers. For example, 1 must be represented as `$(1.)` or `$(1.0)` to be parsed correctly. This PR fixes that problem and adds a regression test. The root of the problem was that the formatting verb `%#v` does not have the right behavior for integers. We fix it by deferring to custom `String()` function for the float operand types. Fixes #387 Closes #388
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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