59 lines
1.1 KiB
Go
59 lines
1.1 KiB
Go
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// 2 november 2017
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package main
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import (
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"fmt"
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)
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type fixed1616 uint32
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type fixed214 uint16
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func fixed1616To214(f fixed1616) fixed214 {
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f += 0x00000002
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g := int32(f) >> 2
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return fixed214(uint32(g) & 0xFFFF)
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}
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func (f fixed1616) In214Range() bool {
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base := int16((f >> 16) & 0xFFFF)
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return base >= -2 && base < 2
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}
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func (f fixed1616) String() string {
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base := int16((f >> 16) & 0xFFFF)
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frac := float64(f & 0xFFFF) / 65536
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res := float64(base) + frac
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return fmt.Sprintf("%f 0x%08X", res, uint32(f))
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}
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func (f fixed214) String() string {
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base := []int16{
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0,
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1,
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-2,
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-1,
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}[(f & 0xC000) >> 14]
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frac := float64(f & 0x3FFF) / 16384
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res := float64(base) + frac
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return fmt.Sprintf("%f 0x%04X", res, uint16(f))
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}
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func main() {
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fmt.Println(fixed214(0x7fff))
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fmt.Println(fixed214(0x8000))
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fmt.Println(fixed214(0x4000))
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fmt.Println(fixed214(0xc000))
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fmt.Println(fixed214(0x7000))
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fmt.Println(fixed214(0x0000))
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fmt.Println(fixed214(0x0001))
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fmt.Println(fixed214(0xffff))
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fmt.Println()
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for i := uint64(0x00000000); i <= 0xFFFFFFFF; i++ {
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j := fixed1616(i)
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if !j.In214Range() { continue }
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fmt.Println(j, "->", fixed1616To214(j))
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}
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}
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