--- /dev/null
+/* adler32_rvv.c - RVV version of adler32
+ * Copyright (C) 2023 SiFive, Inc. All rights reserved.
+ * Contributed by Alex Chiang <alex.chiang@sifive.com>
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#ifdef RISCV_RVV
+
+#include <riscv_vector.h>
+#include <stdint.h>
+
+#include "../../zbuild.h"
+#include "../../adler32_p.h"
+
+Z_INTERNAL uint32_t adler32_rvv(uint32_t adler, const uint8_t *buf, size_t len) {
+ /* split Adler-32 into component sums */
+ uint32_t sum2 = (adler >> 16) & 0xffff;
+ adler &= 0xffff;
+
+ /* in case user likes doing a byte at a time, keep it fast */
+ if (len == 1) {
+ return adler32_len_1(adler, buf, sum2);
+ }
+
+ /* initial Adler-32 value (deferred check for len == 1 speed) */
+ if (buf == NULL)
+ return 1L;
+
+ /* in case short lengths are provided, keep it somewhat fast */
+ if (len < 16) {
+ return adler32_len_16(adler, buf, len, sum2);
+ }
+
+ size_t left = len;
+ size_t vl = __riscv_vsetvlmax_e8m1();
+ vl = vl > 256 ? 256 : vl;
+ vuint32m4_t v_buf32_accu = __riscv_vmv_v_x_u32m4(0, vl);
+ vuint32m4_t v_adler32_prev_accu = __riscv_vmv_v_x_u32m4(0, vl);
+ vuint16m2_t v_buf16_accu;
+
+ /*
+ * We accumulate 8-bit data, and to prevent overflow, we have to use a 32-bit accumulator.
+ * However, adding 8-bit data into a 32-bit accumulator isn't efficient. We use 16-bit & 32-bit
+ * accumulators to boost performance.
+ *
+ * The block_size is the largest multiple of vl that <= 256, because overflow would occur when
+ * vl > 256 (255 * 256 <= UINT16_MAX).
+ *
+ * We accumulate 8-bit data into a 16-bit accumulator and then
+ * move the data into the 32-bit accumulator at the last iteration.
+ */
+ size_t block_size = (256 / vl) * vl;
+ while (left >= block_size) {
+ v_buf16_accu = __riscv_vmv_v_x_u16m2(0, vl);
+ size_t subprob = block_size;
+ while (subprob > 0) {
+ vuint8m1_t v_buf8 = __riscv_vle8_v_u8m1(buf, vl);
+ v_adler32_prev_accu = __riscv_vwaddu_wv_u32m4(v_adler32_prev_accu, v_buf16_accu, vl);
+ v_buf16_accu = __riscv_vwaddu_wv_u16m2(v_buf16_accu, v_buf8, vl);
+ buf += vl;
+ subprob -= vl;
+ }
+ v_adler32_prev_accu = __riscv_vmacc_vx_u32m4(v_adler32_prev_accu, block_size / vl, v_buf32_accu, vl);
+ v_buf32_accu = __riscv_vwaddu_wv_u32m4(v_buf32_accu, v_buf16_accu, vl);
+ left -= block_size;
+ }
+ v_adler32_prev_accu = __riscv_vremu_vx_u32m4(v_adler32_prev_accu, BASE, vl);
+
+ v_buf16_accu = __riscv_vmv_v_x_u16m2(0, vl);
+ size_t res = left;
+ while (left >= vl) {
+ vuint8m1_t v_buf8 = __riscv_vle8_v_u8m1(buf, vl);
+ v_adler32_prev_accu = __riscv_vwaddu_wv_u32m4(v_adler32_prev_accu, v_buf16_accu, vl);
+ v_buf16_accu = __riscv_vwaddu_wv_u16m2(v_buf16_accu, v_buf8, vl);
+ buf += vl;
+ left -= vl;
+ }
+ v_adler32_prev_accu = __riscv_vmacc_vx_u32m4(v_adler32_prev_accu, res / vl, v_buf32_accu, vl);
+ v_buf32_accu = __riscv_vwaddu_wv_u32m4(v_buf32_accu, v_buf16_accu, vl);
+
+ vuint32m4_t v_seq = __riscv_vid_v_u32m4(vl);
+ vuint32m4_t v_rev_seq = __riscv_vrsub_vx_u32m4(v_seq, vl, vl);
+ vuint32m4_t v_sum32_accu = __riscv_vmul_vv_u32m4(v_buf32_accu, v_rev_seq, vl);
+
+ v_sum32_accu = __riscv_vadd_vv_u32m4(v_sum32_accu, __riscv_vmul_vx_u32m4(v_adler32_prev_accu, vl, vl), vl);
+
+ vuint32m1_t v_sum2_sum = __riscv_vmv_s_x_u32m1(0, vl);
+ v_sum2_sum = __riscv_vredsum_vs_u32m4_u32m1(v_sum32_accu, v_sum2_sum, vl);
+ uint32_t sum2_sum = __riscv_vmv_x_s_u32m1_u32(v_sum2_sum);
+
+ sum2 += (sum2_sum + adler * (len - left));
+
+ vuint32m1_t v_adler_sum = __riscv_vmv_s_x_u32m1(0, vl);
+ v_adler_sum = __riscv_vredsum_vs_u32m4_u32m1(v_buf32_accu, v_adler_sum, vl);
+ uint32_t adler_sum = __riscv_vmv_x_s_u32m1_u32(v_adler_sum);
+
+ adler += adler_sum;
+
+ while (left--) {
+ adler += *buf++;
+ sum2 += adler;
+ }
+
+ sum2 %= BASE;
+ adler %= BASE;
+
+ return adler | (sum2 << 16);
+}
+
+#endif // RISCV_RVV
projects / thirdparty / zlib-ng.git / commitdiff
