rscrypto 0.1.1

Pure Rust cryptography, hardware-accelerated: BLAKE3, SHA-2/3, AES-GCM, ChaCha20-Poly1305, Ed25519, X25519, HMAC, HKDF, Argon2, CRC. no_std, WASM, ten CPU architectures.
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
//! s390x hardware-accelerated CRC-64 kernels (XZ + NVME).
//!
//! This is a VGFM implementation derived from the Intel/TiKV folding
//! algorithm (also used by `crc64fast` / `crc64fast-nvme`).
//!
//! # Safety
//!
//! Uses `unsafe` for s390x vector + inline assembly. Callers must ensure the
//! required CPU features are available before executing the accelerated path
//! (the dispatcher does this).
#![allow(unsafe_code)]
#![allow(dead_code)] // Kernels wired up via dispatcher
// SAFETY: All indexing is over fixed-size arrays with in-bounds constant indices.
#![allow(clippy::indexing_slicing)]
// This module is intrinsics-heavy; unsafe blocks are per-function with SAFETY justifications.

use core::{
  arch::asm,
  mem::MaybeUninit,
  ops::{BitXor, BitXorAssign},
  simd::i64x2,
};

use crate::checksum::common::{
  clmul::{Crc64ClmulConstants, fold16_coeff_for_bytes},
  tables::{CRC64_NVME_POLY, CRC64_XZ_POLY},
};

type Block = [u64; 16]; // 128 bytes (8×16B lanes)

#[repr(transparent)]
#[derive(Copy, Clone, Debug)]
struct Simd(i64x2);

impl BitXor for Simd {
  type Output = Self;

  #[inline]
  fn bitxor(self, other: Self) -> Self {
    Self(self.0 ^ other.0)
  }
}

impl BitXorAssign for Simd {
  #[inline]
  fn bitxor_assign(&mut self, other: Self) {
    *self = *self ^ other;
  }
}

impl Simd {
  #[inline]
  fn new(high: u64, low: u64) -> Self {
    // On s390x, vector element 0 maps to the most-significant 64 bits.
    Self(i64x2::from_array([high.cast_signed(), low.cast_signed()]))
  }

  #[inline]
  fn low_64(self) -> u64 {
    self.0.to_array()[1].cast_unsigned()
  }

  #[inline]
  fn high_64(self) -> u64 {
    self.0.to_array()[0].cast_unsigned()
  }

  #[inline]
  #[target_feature(enable = "vector")]
  unsafe fn vgfm(a: i64x2, b: i64x2) -> i64x2 {
    // SAFETY: Caller guarantees the s390x vector facility is available
    // (verified by dispatch). The VGFM instruction operates on pure register
    // values with no memory access.
    unsafe {
      let out: i64x2;
      asm!(
        "vgfm {out}, {a}, {b}, 3",
        out = lateout(vreg) out,
        a = in(vreg) a,
        b = in(vreg) b,
        options(nomem, nostack, pure)
      );
      out
    }
  }

  #[inline]
  #[target_feature(enable = "vector")]
  unsafe fn mul64(a: u64, b: u64) -> Self {
    // SAFETY: Caller guarantees the s390x vector facility is available.
    // vgfm operates on pure register values.
    unsafe {
      let va = Self::new(0, a);
      let vb = Self::new(0, b);
      Self(Self::vgfm(va.0, vb.0))
    }
  }

  /// Fold 16 bytes: `(coeff.low ⊗ self.low) ⊕ (coeff.high ⊗ self.high)`.
  #[inline]
  #[target_feature(enable = "vector")]
  unsafe fn fold_16(self, coeff: Self) -> Self {
    // SAFETY: Caller guarantees the s390x vector facility is available.
    // vgfm operates on pure register values.
    unsafe { Self(Self::vgfm(self.0, coeff.0)) }
  }

  /// Fold 8 bytes: `self.high ⊕ (coeff ⊗ self.low)`.
  #[inline]
  #[target_feature(enable = "vector")]
  unsafe fn fold_8(self, coeff: u64) -> Self {
    // SAFETY: Caller guarantees the s390x vector facility is available.
    // mul64 and XOR are pure register computations.
    unsafe {
      let prod = Self::mul64(self.low_64(), coeff);
      prod ^ Self::new(0, self.high_64())
    }
  }

  /// Barrett reduction to finalize the CRC.
  #[inline]
  #[target_feature(enable = "vector")]
  unsafe fn barrett(self, poly: u64, mu: u64) -> u64 {
    // SAFETY: Caller guarantees the s390x vector facility is available.
    // mul64 and XOR are pure register computations.
    unsafe {
      let t1 = Self::mul64(self.low_64(), mu).low_64();
      let l = Self::mul64(t1, poly);
      (self ^ l).high_64() ^ t1
    }
  }
}

// ─────────────────────────────────────────────────────────────────────────────
// Multi-stream coefficients (compile-time)
// ─────────────────────────────────────────────────────────────────────────────

// 2-way: update step shifts by 2×128B = 256B.
const XZ_FOLD_256B: (u64, u64) = fold16_coeff_for_bytes(CRC64_XZ_POLY, 256);
const NVME_FOLD_256B: (u64, u64) = fold16_coeff_for_bytes(CRC64_NVME_POLY, 256);

// 4-way: update step shifts by 4×128B = 512B, combine shifts by 3/2/1 blocks.
const XZ_FOLD_512B: (u64, u64) = fold16_coeff_for_bytes(CRC64_XZ_POLY, 512);
const NVME_FOLD_512B: (u64, u64) = fold16_coeff_for_bytes(CRC64_NVME_POLY, 512);
const XZ_COMBINE_4WAY: [(u64, u64); 3] = [
  fold16_coeff_for_bytes(CRC64_XZ_POLY, 384),
  fold16_coeff_for_bytes(CRC64_XZ_POLY, 256),
  fold16_coeff_for_bytes(CRC64_XZ_POLY, 128),
];
const NVME_COMBINE_4WAY: [(u64, u64); 3] = [
  fold16_coeff_for_bytes(CRC64_NVME_POLY, 384),
  fold16_coeff_for_bytes(CRC64_NVME_POLY, 256),
  fold16_coeff_for_bytes(CRC64_NVME_POLY, 128),
];

// ─────────────────────────────────────────────────────────────────────────────
// Load helpers (endianness)
// ─────────────────────────────────────────────────────────────────────────────

#[inline(always)]
fn load_block(block: &Block) -> [Simd; 8] {
  let mut out = MaybeUninit::<[Simd; 8]>::uninit();
  let base = out.as_mut_ptr().cast::<Simd>();

  let mut i = 0;
  while i < 8 {
    let low = u64::from_le(block[i * 2]);
    let high = u64::from_le(block[i * 2 + 1]);
    // SAFETY: `base` points to a `[Simd; 8]` buffer and `i` is in-bounds.
    unsafe {
      base.add(i).write(Simd::new(high, low));
    }
    i = i.strict_add(1);
  }

  // SAFETY: all 8 elements are initialized above.
  unsafe { out.assume_init() }
}

// ─────────────────────────────────────────────────────────────────────────────
// Folding helpers
// ─────────────────────────────────────────────────────────────────────────────

#[inline(always)]
unsafe fn fold_tail(x: [Simd; 8], consts: &Crc64ClmulConstants) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // All fold_16 / fold_8 / barrett calls are pure VGFM register computations.
  // Array indexing is over fixed-size [Simd; 8] with constant indices 0..7.
  unsafe {
    // Tail reduction (8×16B → 1×16B), unrolled for throughput.
    let c0 = Simd::new(consts.tail_fold_16b[0].0, consts.tail_fold_16b[0].1);
    let c1 = Simd::new(consts.tail_fold_16b[1].0, consts.tail_fold_16b[1].1);
    let c2 = Simd::new(consts.tail_fold_16b[2].0, consts.tail_fold_16b[2].1);
    let c3 = Simd::new(consts.tail_fold_16b[3].0, consts.tail_fold_16b[3].1);
    let c4 = Simd::new(consts.tail_fold_16b[4].0, consts.tail_fold_16b[4].1);
    let c5 = Simd::new(consts.tail_fold_16b[5].0, consts.tail_fold_16b[5].1);
    let c6 = Simd::new(consts.tail_fold_16b[6].0, consts.tail_fold_16b[6].1);

    let mut acc = x[7];
    acc ^= x[0].fold_16(c0);
    acc ^= x[1].fold_16(c1);
    acc ^= x[2].fold_16(c2);
    acc ^= x[3].fold_16(c3);
    acc ^= x[4].fold_16(c4);
    acc ^= x[5].fold_16(c5);
    acc ^= x[6].fold_16(c6);

    acc.fold_8(consts.fold_8b).barrett(consts.poly, consts.mu)
  }
}

#[inline]
#[target_feature(enable = "vector")]
unsafe fn fold_block_128(x: &mut [Simd; 8], chunk: &[Simd; 8], coeff: Simd) {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // All fold_16 calls are pure VGFM register computations.
  // Array indexing is over fixed-size [Simd; 8] with constant indices 0..7.
  unsafe {
    x[0] = chunk[0] ^ x[0].fold_16(coeff);
    x[1] = chunk[1] ^ x[1].fold_16(coeff);
    x[2] = chunk[2] ^ x[2].fold_16(coeff);
    x[3] = chunk[3] ^ x[3].fold_16(coeff);
    x[4] = chunk[4] ^ x[4].fold_16(coeff);
    x[5] = chunk[5] ^ x[5].fold_16(coeff);
    x[6] = chunk[6] ^ x[6].fold_16(coeff);
    x[7] = chunk[7] ^ x[7].fold_16(coeff);
  }
}

#[target_feature(enable = "vector")]
unsafe fn update_simd(state: u64, first: &Block, rest: &[Block], consts: &Crc64ClmulConstants) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // All fold operations are pure VGFM register computations.
  // Block iteration is bounded by the slice length; no out-of-bounds access.
  unsafe {
    let mut x = load_block(first);

    // XOR the initial CRC into the first lane.
    x[0] ^= Simd::new(0, state);

    // 128-byte folding.
    let coeff = Simd::new(consts.fold_128b.0, consts.fold_128b.1);
    for block in rest {
      let chunk = load_block(block);
      fold_block_128(&mut x, &chunk, coeff);
    }

    fold_tail(x, consts)
  }
}

#[target_feature(enable = "vector")]
unsafe fn update_simd_2way(state: u64, blocks: &[Block], fold_256b: (u64, u64), consts: &Crc64ClmulConstants) -> u64 {
  debug_assert!(!blocks.is_empty());

  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // All fold operations are pure VGFM register computations.
  // Loop index `i` advances by 2 and is bounded by `even` (≤ blocks.len()),
  // so `blocks[i]` and `blocks[i + 1]` are always in-bounds.
  unsafe {
    if blocks.len() < 2 {
      let Some((first, rest)) = blocks.split_first() else {
        return state;
      };
      return update_simd(state, first, rest, consts);
    }

    let even = blocks.len() & !1usize;

    let coeff_256 = Simd::new(fold_256b.0, fold_256b.1);
    let coeff_128 = Simd::new(consts.fold_128b.0, consts.fold_128b.1);

    let mut s0 = load_block(&blocks[0]);
    let mut s1 = load_block(&blocks[1]);

    // Inject CRC into stream 0.
    s0[0] ^= Simd::new(0, state);

    let mut i = 2;
    while i < even {
      let b0 = load_block(&blocks[i]);
      let b1 = load_block(&blocks[i.strict_add(1)]);
      fold_block_128(&mut s0, &b0, coeff_256);
      fold_block_128(&mut s1, &b1, coeff_256);
      i = i.strict_add(2);
    }

    // Merge streams: A·s0 ⊕ s1 (A = shift by 128B).
    let mut combined = s1;
    combined[0] ^= s0[0].fold_16(coeff_128);
    combined[1] ^= s0[1].fold_16(coeff_128);
    combined[2] ^= s0[2].fold_16(coeff_128);
    combined[3] ^= s0[3].fold_16(coeff_128);
    combined[4] ^= s0[4].fold_16(coeff_128);
    combined[5] ^= s0[5].fold_16(coeff_128);
    combined[6] ^= s0[6].fold_16(coeff_128);
    combined[7] ^= s0[7].fold_16(coeff_128);

    // Handle any remaining block (odd tail) sequentially.
    if even != blocks.len() {
      let tail = load_block(&blocks[even]);
      fold_block_128(&mut combined, &tail, coeff_128);
    }

    fold_tail(combined, consts)
  } // unsafe
}

#[target_feature(enable = "vector")]
unsafe fn update_simd_4way(
  state: u64,
  blocks: &[Block],
  fold_512b: (u64, u64),
  combine: &[(u64, u64); 3],
  consts: &Crc64ClmulConstants,
) -> u64 {
  debug_assert!(!blocks.is_empty());

  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // All fold operations are pure VGFM register computations.
  // Loop index `i` advances by 4 and is bounded by `aligned` (≤ blocks.len()),
  // so `blocks[i..i+3]` are always in-bounds. Tail processing uses iterator.
  unsafe {
    if blocks.len() < 4 {
      let Some((first, rest)) = blocks.split_first() else {
        return state;
      };
      return update_simd(state, first, rest, consts);
    }

    let aligned = blocks.len().strict_div(4).strict_mul(4);

    let coeff_512 = Simd::new(fold_512b.0, fold_512b.1);
    let coeff_128 = Simd::new(consts.fold_128b.0, consts.fold_128b.1);
    let c384 = Simd::new(combine[0].0, combine[0].1);
    let c256 = Simd::new(combine[1].0, combine[1].1);
    let c128 = Simd::new(combine[2].0, combine[2].1);

    let mut s0 = load_block(&blocks[0]);
    let mut s1 = load_block(&blocks[1]);
    let mut s2 = load_block(&blocks[2]);
    let mut s3 = load_block(&blocks[3]);

    // Inject CRC into stream 0.
    s0[0] ^= Simd::new(0, state);

    let mut i = 4;
    while i < aligned {
      let b0 = load_block(&blocks[i]);
      let b1 = load_block(&blocks[i.strict_add(1)]);
      let b2 = load_block(&blocks[i.strict_add(2)]);
      let b3 = load_block(&blocks[i.strict_add(3)]);
      fold_block_128(&mut s0, &b0, coeff_512);
      fold_block_128(&mut s1, &b1, coeff_512);
      fold_block_128(&mut s2, &b2, coeff_512);
      fold_block_128(&mut s3, &b3, coeff_512);
      i = i.strict_add(4);
    }

    // Merge: A^3·s0 ⊕ A^2·s1 ⊕ A·s2 ⊕ s3.
    let mut combined = s3;
    combined[0] ^= s2[0].fold_16(c128);
    combined[1] ^= s2[1].fold_16(c128);
    combined[2] ^= s2[2].fold_16(c128);
    combined[3] ^= s2[3].fold_16(c128);
    combined[4] ^= s2[4].fold_16(c128);
    combined[5] ^= s2[5].fold_16(c128);
    combined[6] ^= s2[6].fold_16(c128);
    combined[7] ^= s2[7].fold_16(c128);

    combined[0] ^= s1[0].fold_16(c256);
    combined[1] ^= s1[1].fold_16(c256);
    combined[2] ^= s1[2].fold_16(c256);
    combined[3] ^= s1[3].fold_16(c256);
    combined[4] ^= s1[4].fold_16(c256);
    combined[5] ^= s1[5].fold_16(c256);
    combined[6] ^= s1[6].fold_16(c256);
    combined[7] ^= s1[7].fold_16(c256);

    combined[0] ^= s0[0].fold_16(c384);
    combined[1] ^= s0[1].fold_16(c384);
    combined[2] ^= s0[2].fold_16(c384);
    combined[3] ^= s0[3].fold_16(c384);
    combined[4] ^= s0[4].fold_16(c384);
    combined[5] ^= s0[5].fold_16(c384);
    combined[6] ^= s0[6].fold_16(c384);
    combined[7] ^= s0[7].fold_16(c384);

    for block in &blocks[aligned..] {
      let b = load_block(block);
      fold_block_128(&mut combined, &b, coeff_128);
    }

    fold_tail(combined, consts)
  } // unsafe
}

// ─────────────────────────────────────────────────────────────────────────────
// Public kernels (XZ + NVME)
// ─────────────────────────────────────────────────────────────────────────────

#[target_feature(enable = "vector")]
unsafe fn crc64_vgfm(mut state: u64, bytes: &[u8], consts: &Crc64ClmulConstants, tables: &[[u64; 256]; 16]) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // align_to produces valid sub-slices. from_raw_parts length is exact because
  // blocks_u64.len() is a multiple of 16 and tail_u64 is from the aligned middle.
  unsafe {
    let (left, middle, right) = bytes.align_to::<u64>();

    state = super::portable::crc64_slice16(state, left, tables);

    let block_u64s = middle.len() & !15usize;
    let (blocks_u64, tail_u64) = middle.split_at(block_u64s);

    if !blocks_u64.is_empty() {
      // SAFETY: `blocks_u64` length is a multiple of 16, so casting to `[u64; 16]` is valid.
      let blocks: &[Block] = core::slice::from_raw_parts(blocks_u64.as_ptr().cast(), blocks_u64.len().strict_div(16));
      if let Some((first, rest)) = blocks.split_first() {
        state = update_simd(state, first, rest, consts);
      }
    }

    if !tail_u64.is_empty() {
      // SAFETY: `tail_u64` is a subslice of the aligned u64 middle region.
      let tail_bytes = core::slice::from_raw_parts(tail_u64.as_ptr().cast(), tail_u64.len() * 8);
      state = super::portable::crc64_slice16(state, tail_bytes, tables);
    }

    super::portable::crc64_slice16(state, right, tables)
  }
}

#[target_feature(enable = "vector")]
unsafe fn crc64_vgfm_2way(
  mut state: u64,
  bytes: &[u8],
  fold_256b: (u64, u64),
  consts: &Crc64ClmulConstants,
  tables: &[[u64; 256]; 16],
) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // align_to produces valid sub-slices. from_raw_parts length is exact.
  unsafe {
    let (left, middle, right) = bytes.align_to::<u64>();

    state = super::portable::crc64_slice16(state, left, tables);

    let block_u64s = middle.len() & !15usize;
    let (blocks_u64, tail_u64) = middle.split_at(block_u64s);

    if !blocks_u64.is_empty() {
      // SAFETY: `blocks_u64` length is a multiple of 16, so casting to `[u64; 16]` is valid.
      let blocks: &[Block] = core::slice::from_raw_parts(blocks_u64.as_ptr().cast(), blocks_u64.len().strict_div(16));
      state = update_simd_2way(state, blocks, fold_256b, consts);
    }

    if !tail_u64.is_empty() {
      // SAFETY: `tail_u64` is a subslice of the aligned u64 middle region.
      let tail_bytes = core::slice::from_raw_parts(tail_u64.as_ptr().cast(), tail_u64.len() * 8);
      state = super::portable::crc64_slice16(state, tail_bytes, tables);
    }

    super::portable::crc64_slice16(state, right, tables)
  }
}

#[target_feature(enable = "vector")]
unsafe fn crc64_vgfm_4way(
  mut state: u64,
  bytes: &[u8],
  fold_512b: (u64, u64),
  combine: &[(u64, u64); 3],
  consts: &Crc64ClmulConstants,
  tables: &[[u64; 256]; 16],
) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  // align_to produces valid sub-slices. from_raw_parts length is exact.
  unsafe {
    let (left, middle, right) = bytes.align_to::<u64>();

    state = super::portable::crc64_slice16(state, left, tables);

    let block_u64s = middle.len() & !15usize;
    let (blocks_u64, tail_u64) = middle.split_at(block_u64s);

    if !blocks_u64.is_empty() {
      // SAFETY: `blocks_u64` length is a multiple of 16, so casting to `[u64; 16]` is valid.
      let blocks: &[Block] = core::slice::from_raw_parts(blocks_u64.as_ptr().cast(), blocks_u64.len().strict_div(16));
      state = update_simd_4way(state, blocks, fold_512b, combine, consts);
    }

    if !tail_u64.is_empty() {
      // SAFETY: `tail_u64` is a subslice of the aligned u64 middle region.
      let tail_bytes = core::slice::from_raw_parts(tail_u64.as_ptr().cast(), tail_u64.len() * 8);
      state = super::portable::crc64_slice16(state, tail_bytes, tables);
    }

    super::portable::crc64_slice16(state, right, tables)
  }
}

/// CRC-64-XZ using VGFM folding.
///
/// # Safety
///
/// Requires the s390x vector facility. Caller must verify via
/// `crate::platform::caps().has(s390x::VECTOR)`.
#[target_feature(enable = "vector")]
pub(crate) unsafe fn crc64_xz_vgfm(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  unsafe {
    crc64_vgfm(
      crc,
      data,
      &crate::checksum::common::clmul::CRC64_XZ_CLMUL,
      &super::kernel_tables::XZ_TABLES_16,
    )
  }
}

/// CRC-64-XZ using VGFM folding (2-way ILP variant).
///
/// # Safety
///
/// Requires the s390x vector facility. Caller must verify via
/// `crate::platform::caps().has(s390x::VECTOR)`.
#[target_feature(enable = "vector")]
pub(crate) unsafe fn crc64_xz_vgfm_2way(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  unsafe {
    crc64_vgfm_2way(
      crc,
      data,
      XZ_FOLD_256B,
      &crate::checksum::common::clmul::CRC64_XZ_CLMUL,
      &super::kernel_tables::XZ_TABLES_16,
    )
  }
}

/// CRC-64-XZ using VGFM folding (4-way ILP variant).
///
/// # Safety
///
/// Requires the s390x vector facility. Caller must verify via
/// `crate::platform::caps().has(s390x::VECTOR)`.
#[target_feature(enable = "vector")]
pub(crate) unsafe fn crc64_xz_vgfm_4way(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  unsafe {
    crc64_vgfm_4way(
      crc,
      data,
      XZ_FOLD_512B,
      &XZ_COMBINE_4WAY,
      &crate::checksum::common::clmul::CRC64_XZ_CLMUL,
      &super::kernel_tables::XZ_TABLES_16,
    )
  }
}

/// CRC-64-NVME using VGFM folding.
///
/// # Safety
///
/// Requires the s390x vector facility. Caller must verify via
/// `crate::platform::caps().has(s390x::VECTOR)`.
#[target_feature(enable = "vector")]
pub(crate) unsafe fn crc64_nvme_vgfm(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  unsafe {
    crc64_vgfm(
      crc,
      data,
      &crate::checksum::common::clmul::CRC64_NVME_CLMUL,
      &super::kernel_tables::NVME_TABLES_16,
    )
  }
}

/// CRC-64-NVME using VGFM folding (2-way ILP variant).
///
/// # Safety
///
/// Requires the s390x vector facility. Caller must verify via
/// `crate::platform::caps().has(s390x::VECTOR)`.
#[target_feature(enable = "vector")]
pub(crate) unsafe fn crc64_nvme_vgfm_2way(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  unsafe {
    crc64_vgfm_2way(
      crc,
      data,
      NVME_FOLD_256B,
      &crate::checksum::common::clmul::CRC64_NVME_CLMUL,
      &super::kernel_tables::NVME_TABLES_16,
    )
  }
}

/// CRC-64-NVME using VGFM folding (4-way ILP variant).
///
/// # Safety
///
/// Requires the s390x vector facility. Caller must verify via
/// `crate::platform::caps().has(s390x::VECTOR)`.
#[target_feature(enable = "vector")]
pub(crate) unsafe fn crc64_nvme_vgfm_4way(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Caller guarantees the s390x vector facility is available (dispatch check).
  unsafe {
    crc64_vgfm_4way(
      crc,
      data,
      NVME_FOLD_512B,
      &NVME_COMBINE_4WAY,
      &crate::checksum::common::clmul::CRC64_NVME_CLMUL,
      &super::kernel_tables::NVME_TABLES_16,
    )
  }
}

// ─────────────────────────────────────────────────────────────────────────────
// Safe wrappers
// ─────────────────────────────────────────────────────────────────────────────

#[inline]
pub fn crc64_xz_vgfm_safe(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Dispatcher verifies VECTOR facility before selecting this kernel.
  unsafe { crc64_xz_vgfm(crc, data) }
}

#[inline]
pub fn crc64_xz_vgfm_2way_safe(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Dispatcher verifies VECTOR facility before selecting this kernel.
  unsafe { crc64_xz_vgfm_2way(crc, data) }
}

#[inline]
pub fn crc64_xz_vgfm_4way_safe(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Dispatcher verifies VECTOR facility before selecting this kernel.
  unsafe { crc64_xz_vgfm_4way(crc, data) }
}

#[inline]
pub fn crc64_nvme_vgfm_safe(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Dispatcher verifies VECTOR facility before selecting this kernel.
  unsafe { crc64_nvme_vgfm(crc, data) }
}

#[inline]
pub fn crc64_nvme_vgfm_2way_safe(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Dispatcher verifies VECTOR facility before selecting this kernel.
  unsafe { crc64_nvme_vgfm_2way(crc, data) }
}

#[inline]
pub fn crc64_nvme_vgfm_4way_safe(crc: u64, data: &[u8]) -> u64 {
  // SAFETY: Dispatcher verifies VECTOR facility before selecting this kernel.
  unsafe { crc64_nvme_vgfm_4way(crc, data) }
}