47 lines
1.3 KiB
Rust
47 lines
1.3 KiB
Rust
/* Implemnetation of *m_fixed.c/h
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This provides fixed-point arithmetic as 32-bit 16.16
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*/
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pub const FRACBITS: i32 = 16;
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pub const FRACUNIT: i32 = 1 << FRACBITS;
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pub const MININT: i32 = 0x80000000;
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pub const MAXINT: i32 = 0x7fffffff;
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/// Struct representing a fixed point 32-bit value
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#[derive(Copy, Clone, PartialEq, Debug)]
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pub struct FixedPoint {
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pub value: i32,
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}
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impl FixedPoint {
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#[allow(non_snake_case)]
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pub fn FixedMul(a: FixedPoint, b: FixedPoint) -> FixedPoint {
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let value = ((a.value as u64) * (b.value as u64) >> FRACBITS) as i32;
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FixedPoint{value}
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}
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#[allow(non_snake_case)]
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pub fn FixedDiv(a: FixedPoint, b: FixedPoint) -> FixedPoint {
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if (i32::abs(a.value) >> 14) >= i32::abs(b.value) {
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if a.value^b.value == 0 {
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FixedPoint{value: MININT};
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}
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else {
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FixedPoint{value: MAXINT};
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}
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}
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FixedPoint::FixedDiv2(a,b)
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}
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#[allow(non_snake_case)]
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pub fn FixedDiv2(a: FixedPoint, b: FixedPoint) -> FixedPoint {
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let c: f64 = ((a.value as f64) / (b.value as f64)) * FRACUNIT as f64;
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if c >= 2147483648.0 || c < -2147483648.0 {
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panic!("FixedDiv: divide by zero");
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}
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FixedPoint { value: c as i32 }
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}
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}
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