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Armv8.1-M: Add native Keccak x4 XORBytes and ExtractBytes #972

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a61e9cd
Unit Tests: Extend Keccak x4 test to cover xor_bytes and extract_bytes
mkannwischer Feb 19, 2026
1601cb6
FIPS202: Add native x4 XOR/extract bytes interface
mkannwischer Feb 19, 2026
3823f1f
Armv8.1-M: Add native Keccak x4 XORBytes and ExtractBytes
mkannwischer Feb 19, 2026
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48 changes: 48 additions & 0 deletions dev/fips202/armv81m/mve.h
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Original file line number Diff line number Diff line change
Expand Up @@ -11,12 +11,18 @@

/* Part of backend API */
#define MLD_USE_FIPS202_X4_NATIVE
#define MLD_USE_FIPS202_X4_XOR_BYTES_NATIVE
#define MLD_USE_FIPS202_X4_EXTRACT_BYTES_NATIVE
/* Guard for assembly file */
#define MLD_FIPS202_ARMV81M_NEED_X4

#if !defined(__ASSEMBLER__)
#include "../api.h"

/*
* Native x4 permutation
* State is kept in bit-interleaved format.
*/
#define mld_keccak_f1600_x4_native_impl \
MLD_NAMESPACE(keccak_f1600_x4_native_impl)
int mld_keccak_f1600_x4_native_impl(uint64_t *state);
Expand All @@ -27,6 +33,48 @@ static MLD_INLINE int mld_keccak_f1600_x4_native(uint64_t *state)
return mld_keccak_f1600_x4_native_impl(state);
}

/*
* Native x4 XOR bytes (with on-the-fly bit interleaving)
*/
#define mld_keccak_f1600_x4_state_xor_bytes \
MLD_NAMESPACE(keccak_f1600_x4_state_xor_bytes_asm)
void mld_keccak_f1600_x4_state_xor_bytes(void *state, const uint8_t *data0,
const uint8_t *data1,
const uint8_t *data2,
const uint8_t *data3, unsigned offset,
unsigned length);

MLD_MUST_CHECK_RETURN_VALUE
static MLD_INLINE int mld_keccakf1600_xor_bytes_x4_native(
uint64_t *state, const uint8_t *data0, const uint8_t *data1,
const uint8_t *data2, const uint8_t *data3, unsigned offset,
unsigned length)
{
mld_keccak_f1600_x4_state_xor_bytes(state, data0, data1, data2, data3, offset,
length);
return MLD_NATIVE_FUNC_SUCCESS;
}

/*
* Native x4 extract bytes (with on-the-fly bit de-interleaving)
*/
#define mld_keccak_f1600_x4_state_extract_bytes \
MLD_NAMESPACE(keccak_f1600_x4_state_extract_bytes_asm)
void mld_keccak_f1600_x4_state_extract_bytes(void *state, uint8_t *data0,
uint8_t *data1, uint8_t *data2,
uint8_t *data3, unsigned offset,
unsigned length);

MLD_MUST_CHECK_RETURN_VALUE
static MLD_INLINE int mld_keccakf1600_extract_bytes_x4_native(
uint64_t *state, uint8_t *data0, uint8_t *data1, uint8_t *data2,
uint8_t *data3, unsigned offset, unsigned length)
{
mld_keccak_f1600_x4_state_extract_bytes(state, data0, data1, data2, data3,
offset, length);
return MLD_NATIVE_FUNC_SUCCESS;
}

#endif /* !__ASSEMBLER__ */

#endif /* !MLD_DEV_FIPS202_ARMV81M_MVE_H */
16 changes: 16 additions & 0 deletions dev/fips202/armv81m/src/fips202_native_armv81m.h
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Expand Up @@ -17,4 +17,20 @@ extern const uint32_t mld_keccakf1600_round_constants[48];
void mld_keccak_f1600_x4_mve_asm(uint64_t state[100], uint64_t tmpstate[100],
const uint32_t rc[48]);

#define mld_keccak_f1600_x4_state_xor_bytes_asm \
MLD_NAMESPACE(keccak_f1600_x4_state_xor_bytes_asm)
void mld_keccak_f1600_x4_state_xor_bytes_asm(void *state, const uint8_t *d0,
const uint8_t *d1,
const uint8_t *d2,
const uint8_t *d3, unsigned offset,
unsigned length);

#define mld_keccak_f1600_x4_state_extract_bytes_asm \
MLD_NAMESPACE(keccak_f1600_x4_state_extract_bytes_asm)
void mld_keccak_f1600_x4_state_extract_bytes_asm(void *state, uint8_t *data0,
uint8_t *data1, uint8_t *data2,
uint8_t *data3,
unsigned offset,
unsigned length);

#endif /* !MLD_DEV_FIPS202_ARMV81M_SRC_FIPS202_NATIVE_ARMV81M_H */
36 changes: 33 additions & 3 deletions dev/fips202/armv81m/src/keccak_f1600_x4_mve.S
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Expand Up @@ -7,15 +7,15 @@

/*yaml
Name: keccak_f1600_x4_mve_asm
Description: Armv8.1-M MVE implementation of 4-way parallel Keccak-f[1600] permutation using bit-interleaved state
Description: Armv8.1-M MVE implementation of batched (x4) Keccak-f[1600] permutation using bit-interleaved state
Signature: void mld_keccak_f1600_x4_mve_asm(void *state, void *tmpstate, const uint32_t *rc)
ABI:
r0:
type: buffer
size_bytes: 800
permissions: read/write
c_parameter: void *state
description: Four bit-interleaved Keccak states (low halves followed by high halves)
description: Bit-interleaved state for 4 Keccak instances (even halves followed by odd halves)
r1:
type: buffer
size_bytes: 800
Expand All @@ -33,6 +33,36 @@
description: register preservation (44) + SIMD registers (64) + temporary storage (128)
*/

// ---------------------------------------------------------------------------
// Bit-interleaving background
// ---------------------------------------------------------------------------
// Each 64-bit Keccak lane is stored as two 32-bit words:
// even half -- bits 0, 2, 4, ..., 62 of the lane
// odd half -- bits 1, 3, 5, ..., 63 of the lane
// This representation allows 64-bit lane rotations (used in the Keccak
// round function) to be implemented as pairs of 32-bit rotations.
//
// Batched (x4) processing:
// Four Keccak instances are processed as a batch. Their states are
// stored interleaved in a single 800-byte buffer: first the even
// halves of all 25 lanes (400 bytes), then the odd halves (400 bytes).
// Within each 16-byte row, the four u32 words correspond to
// instances 0..3 of the same lane, enabling SIMD-parallel operations
// across all four instances.
//
// State memory layout (25 lanes x 4 instances x 2 halves):
// S[i][l]_even/odd = even/odd half of lane l, instance i (u32)
// Each row is 16 bytes (one Q-register).
// Offset Contents
// 0 S[0][ 0]_even, S[1][ 0]_even, S[2][ 0]_even, S[3][ 0]_even
// 16 S[0][ 1]_even, S[1][ 1]_even, S[2][ 1]_even, S[3][ 1]_even
// ...
// 384 S[0][24]_even, S[1][24]_even, S[2][24]_even, S[3][24]_even
// 400 S[0][ 0]_odd, S[1][ 0]_odd, S[2][ 0]_odd, S[3][ 0]_odd
// 416 S[0][ 1]_odd, S[1][ 1]_odd, S[2][ 1]_odd, S[3][ 1]_odd
// ...
// 784 S[0][24]_odd, S[1][24]_odd, S[2][24]_odd, S[3][24]_odd

#include "../../../../common.h"
#if defined(MLD_FIPS202_ARMV81M_NEED_X4) && \
!defined(MLD_CONFIG_MULTILEVEL_NO_SHARED)
Expand Down Expand Up @@ -426,7 +456,7 @@ qA20_l .req q2
.endm

.text
.balign 8
.balign 4
.type MLD_ASM_NAMESPACE(keccak_f1600_x4_mve_asm), %function
.global MLD_ASM_NAMESPACE(keccak_f1600_x4_mve_asm)
MLD_ASM_FN_SYMBOL(keccak_f1600_x4_mve_asm)
Expand Down
105 changes: 5 additions & 100 deletions dev/fips202/armv81m/src/keccak_f1600_x4_mve.c
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Expand Up @@ -12,114 +12,19 @@

#include "fips202_native_armv81m.h"

/*
* TEMPORARY: Bit-interleaving using efficient shift-and-mask operations.
* TODO: Replace with optimized MVE assembly implementations
* (as a part of XORBytes and ExtractBytes)
*/

/* Extract even-indexed bits from 64-bit value into lower 32 bits */
static uint32_t bitinterleave_even(uint64_t x)
{
uint64_t t;
t = x & 0x5555555555555555ULL;
t = (t | (t >> 1)) & 0x3333333333333333ULL;
t = (t | (t >> 2)) & 0x0f0f0f0f0f0f0f0fULL;
t = (t | (t >> 4)) & 0x00ff00ff00ff00ffULL;
t = (t | (t >> 8)) & 0x0000ffff0000ffffULL;
t = (t | (t >> 16)) & 0x00000000ffffffffULL;
return (uint32_t)t;
}

/* Extract odd-indexed bits from 64-bit value into lower 32 bits */
static uint32_t bitinterleave_odd(uint64_t x)
{
return bitinterleave_even(x >> 1);
}

/* Spread 32-bit value across even bit positions of 64-bit result */
static uint64_t spread_even(uint32_t x)
{
uint64_t t = x;
t = (t | (t << 16)) & 0x0000ffff0000ffffULL;
t = (t | (t << 8)) & 0x00ff00ff00ff00ffULL;
t = (t | (t << 4)) & 0x0f0f0f0f0f0f0f0fULL;
t = (t | (t << 2)) & 0x3333333333333333ULL;
t = (t | (t << 1)) & 0x5555555555555555ULL;
return t;
}

/* Combine even and odd 32-bit halves into interleaved 64-bit value */
static uint64_t bitdeinterleave(uint32_t even, uint32_t odd)
{
return spread_even(even) | (spread_even(odd) << 1);
}

/*
* TEMPORARY: Naive C interleaving functions.
* These will be replaced with optimized MVE assembly implementations.
* Keccak-f1600 x4 permutation (on bit-interleaved state)
* State is expected to already be in bit-interleaved format.
*/
static void interleave_4fold(uint64_t *state_4x, const uint64_t *state0,
const uint64_t *state1, const uint64_t *state2,
const uint64_t *state3)
{
uint32_t *state_4xl = (uint32_t *)state_4x;
uint32_t *state_4xh = (uint32_t *)state_4x + 100;

for (size_t i = 0; i < 25; i++)
{
state_4xl[i * 4 + 0] = bitinterleave_even(state0[i]);
state_4xl[i * 4 + 1] = bitinterleave_even(state1[i]);
state_4xl[i * 4 + 2] = bitinterleave_even(state2[i]);
state_4xl[i * 4 + 3] = bitinterleave_even(state3[i]);

state_4xh[i * 4 + 0] = bitinterleave_odd(state0[i]);
state_4xh[i * 4 + 1] = bitinterleave_odd(state1[i]);
state_4xh[i * 4 + 2] = bitinterleave_odd(state2[i]);
state_4xh[i * 4 + 3] = bitinterleave_odd(state3[i]);
}
}

static void deinterleave_4fold(uint64_t *state_4x, uint64_t *state0,
uint64_t *state1, uint64_t *state2,
uint64_t *state3)
{
uint32_t *state_4xl = (uint32_t *)state_4x;
uint32_t *state_4xh = (uint32_t *)state_4x + 100;

for (size_t i = 0; i < 25; i++)
{
state0[i] = bitdeinterleave(state_4xl[i * 4 + 0], state_4xh[i * 4 + 0]);
state1[i] = bitdeinterleave(state_4xl[i * 4 + 1], state_4xh[i * 4 + 1]);
state2[i] = bitdeinterleave(state_4xl[i * 4 + 2], state_4xh[i * 4 + 2]);
state3[i] = bitdeinterleave(state_4xl[i * 4 + 3], state_4xh[i * 4 + 3]);
}
}

#define mld_keccak_f1600_x4_native_impl \
MLD_NAMESPACE(keccak_f1600_x4_native_impl)
int mld_keccak_f1600_x4_native_impl(uint64_t *state)
{
/*
* TEMPORARY: Bit-interleaving using efficient shift-and-mask operations.
* TODO: Replace with optimized MVE assembly implementations
* (as a part of XORBytes and ExtractBytes)
*/
MLD_ALIGN uint64_t state_4x[100];
MLD_ALIGN uint64_t state_4x_tmp[100];

/* Interleave the 4 states into bit-interleaved format */
interleave_4fold(state_4x, &state[0], &state[25], &state[50], &state[75]);

/* Run the permutation */
mld_keccak_f1600_x4_mve_asm(state_4x, state_4x_tmp,
MLD_ALIGN uint64_t state_tmp[100];
mld_keccak_f1600_x4_mve_asm(state, state_tmp,
mld_keccakf1600_round_constants);

/* Deinterleave back to 4 separate states */
deinterleave_4fold(state_4x, &state[0], &state[25], &state[50], &state[75]);

mld_zeroize(state_4x, sizeof(state_4x));
mld_zeroize(state_4x_tmp, sizeof(state_4x_tmp));
mld_zeroize(state_tmp, sizeof(state_tmp));
return MLD_NATIVE_FUNC_SUCCESS;
}

Expand Down
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