tiny.simd.slide

1pub const slide = @import("slide.zig");

1const std = @import("std");23pub fn slideUpLanes(comptime D: type, value: D.Vector, amount: usize) D.Vector {4    std.debug.assert(amount <= D.lane_count);5    const lanes: [D.lane_count]D.Lane = @bitCast(value);6    var result = @as([D.lane_count]D.Lane, @splat(0));7    for (amount..D.lane_count) |index| result[index] = lanes[index - amount];8    return @bitCast(result);9}1011pub fn slideDownLanes(comptime D: type, value: D.Vector, amount: usize) D.Vector {12    std.debug.assert(amount <= D.lane_count);13    const lanes: [D.lane_count]D.Lane = @bitCast(value);14    var result = @as([D.lane_count]D.Lane, @splat(0));15    for (0..D.lane_count - amount) |index| result[index] = lanes[index + amount];16    return @bitCast(result);17}1819pub fn slideUpLanesOr(20    comptime D: type,21    low: D.Vector,22    high: D.Vector,23    amount: usize,24) D.Vector {25    std.debug.assert(amount <= D.lane_count);26    const low_lanes: [D.lane_count]D.Lane = @bitCast(low);27    const high_lanes: [D.lane_count]D.Lane = @bitCast(high);28    var result: [D.lane_count]D.Lane = undefined;29    for (0..D.lane_count) |index| {30        result[index] = if (index < amount) low_lanes[index] else high_lanes[index - amount];31    }32    return @bitCast(result);33}3435pub fn slideDownLanesOr(36    comptime D: type,37    high: D.Vector,38    low: D.Vector,39    amount: usize,40) D.Vector {41    std.debug.assert(amount <= D.lane_count);42    const high_lanes: [D.lane_count]D.Lane = @bitCast(high);43    const low_lanes: [D.lane_count]D.Lane = @bitCast(low);44    var result: [D.lane_count]D.Lane = undefined;45    for (0..D.lane_count) |index| {46        result[index] = if (index < D.lane_count - amount)47            low_lanes[index + amount]48        else49            high_lanes[index];50    }51    return @bitCast(result);52}5354pub fn slide1Up(comptime D: type, value: D.Vector) D.Vector {55    return slideUpLanes(D, value, 1);56}5758pub fn slide1Down(comptime D: type, value: D.Vector) D.Vector {59    return slideDownLanes(D, value, 1);60}6162pub fn slide1UpOr(comptime D: type, fill: D.Lane, value: D.Vector) D.Vector {63    var result = slide1Up(D, value);64    result[0] = fill;65    return result;66}6768pub fn slide1DownOr(comptime D: type, fill: D.Lane, value: D.Vector) D.Vector {69    var result = slide1Down(D, value);70    result[D.lane_count - 1] = fill;71    return result;72}7374pub fn slideUpBlocks(comptime D: type, comptime blocks: usize, value: D.Vector) D.Vector {75    const lanes_per_block = 16 / @sizeOf(D.Lane);76    if (blocks * lanes_per_block > D.lane_count) @compileError("block slide exceeds the vector");77    return slideUpLanes(D, value, blocks * lanes_per_block);78}7980pub fn slideDownBlocks(comptime D: type, comptime blocks: usize, value: D.Vector) D.Vector {81    const lanes_per_block = 16 / @sizeOf(D.Lane);82    if (blocks * lanes_per_block > D.lane_count) @compileError("block slide exceeds the vector");83    return slideDownLanes(D, value, blocks * lanes_per_block);84}8586pub fn slideMaskUpLanes(comptime D: type, mask: D.Mask, amount: usize) D.Mask {87    std.debug.assert(amount <= D.lane_count);88    var lanes: [D.lane_count]bool = undefined;89    inline for (0..D.lane_count) |index| lanes[index] = mask[index];90    var shifted = @as([D.lane_count]bool, @splat(false));91    for (amount..D.lane_count) |index| shifted[index] = lanes[index - amount];92    var result: D.Mask = undefined;93    inline for (0..D.lane_count) |index| result[index] = shifted[index];94    return result;95}9697pub fn slideMaskDownLanes(comptime D: type, mask: D.Mask, amount: usize) D.Mask {98    std.debug.assert(amount <= D.lane_count);99    var lanes: [D.lane_count]bool = undefined;100    inline for (0..D.lane_count) |index| lanes[index] = mask[index];101    var shifted = @as([D.lane_count]bool, @splat(false));102    for (0..D.lane_count - amount) |index| shifted[index] = lanes[index + amount];103    var result: D.Mask = undefined;104    inline for (0..D.lane_count) |index| result[index] = shifted[index];105    return result;106}107108pub fn slideMask1Up(comptime D: type, mask: D.Mask) D.Mask {109    return slideMaskUpLanes(D, mask, 1);110}111112pub fn slideMask1Down(comptime D: type, mask: D.Mask) D.Mask {113    return slideMaskDownLanes(D, mask, 1);114}115116fn verifyLaneType(comptime T: type) !void {117    const simd = @import("root.zig");118    const D = simd.FixedTag(T, 4);119    const zero: D.Vector = @splat(0);120    try std.testing.expect(@reduce(.And, slideUpLanes(D, zero, 2) == zero));121    try std.testing.expect(@reduce(.And, slideDownLanes(D, zero, 2) == zero));122}123124test "Highway slides instantiate every lane type" {125    inline for (.{ u8, i8, u16, i16, u32, i32, u64, i64, f16, f32, f64 }) |T| {126        try verifyLaneType(T);127    }128}129130test "Highway lane slides cross blocks and preserve explicit fill lanes" {131    const simd = @import("root.zig");132    const D = simd.FixedTag(i32, 8);133    const value: D.Vector = .{ 0, 1, 2, 3, 4, 5, 6, 7 };134    const fill: D.Vector = @splat(99);135    try std.testing.expect(@reduce(.And, slideUpLanes(D, value, 3) == @as(D.Vector, .{ 0, 0, 0, 0, 1, 2, 3, 4 })));136    try std.testing.expect(@reduce(.And, slideDownLanes(D, value, 3) == @as(D.Vector, .{ 3, 4, 5, 6, 7, 0, 0, 0 })));137    try std.testing.expect(@reduce(.And, slideUpLanesOr(D, fill, value, 3) == @as(D.Vector, .{ 99, 99, 99, 0, 1, 2, 3, 4 })));138    try std.testing.expect(@reduce(.And, slideDownLanesOr(D, fill, value, 3) == @as(D.Vector, .{ 3, 4, 5, 6, 7, 99, 99, 99 })));139    try std.testing.expect(@reduce(.And, slide1UpOr(D, -1, value) == @as(D.Vector, .{ -1, 0, 1, 2, 3, 4, 5, 6 })));140    try std.testing.expect(@reduce(.And, slide1DownOr(D, -1, value) == @as(D.Vector, .{ 1, 2, 3, 4, 5, 6, 7, -1 })));141}142143test "Highway mask and block slides use the same whole-vector geometry" {144    const simd = @import("root.zig");145    const D = simd.FixedTag(u32, 8);146    const mask: D.Mask = .{ true, false, true, false, false, true, false, true };147    try std.testing.expect(@reduce(.And, slideMaskUpLanes(D, mask, 2) ==148        @as(D.Mask, .{ false, false, true, false, true, false, false, true })));149    try std.testing.expect(@reduce(.And, slideMaskDownLanes(D, mask, 2) ==150        @as(D.Mask, .{ true, false, false, true, false, true, false, false })));151    const value: D.Vector = .{ 0, 1, 2, 3, 4, 5, 6, 7 };152    try std.testing.expect(@reduce(.And, slideUpBlocks(D, 1, value) == @as(D.Vector, .{ 0, 0, 0, 0, 0, 1, 2, 3 })));153    try std.testing.expect(@reduce(.And, slideDownBlocks(D, 1, value) == @as(D.Vector, .{ 4, 5, 6, 7, 0, 0, 0, 0 })));154}