diff --git a/BIBLIOGRAPHY.md b/BIBLIOGRAPHY.md
index 9783c2b7a..1b284974c 100644
--- a/BIBLIOGRAPHY.md
+++ b/BIBLIOGRAPHY.md
@@ -219,7 +219,7 @@ source code and documentation.
   - [dev/x86_64/src/pointwise_acc_l4.S](dev/x86_64/src/pointwise_acc_l4.S)
   - [dev/x86_64/src/pointwise_acc_l5.S](dev/x86_64/src/pointwise_acc_l5.S)
   - [dev/x86_64/src/pointwise_acc_l7.S](dev/x86_64/src/pointwise_acc_l7.S)
-  - [dev/x86_64/src/poly_caddq_avx2.c](dev/x86_64/src/poly_caddq_avx2.c)
+  - [dev/x86_64/src/poly_caddq_avx2.S](dev/x86_64/src/poly_caddq_avx2.S)
   - [dev/x86_64/src/poly_chknorm_avx2.c](dev/x86_64/src/poly_chknorm_avx2.c)
   - [dev/x86_64/src/poly_decompose_32_avx2.c](dev/x86_64/src/poly_decompose_32_avx2.c)
   - [dev/x86_64/src/poly_decompose_88_avx2.c](dev/x86_64/src/poly_decompose_88_avx2.c)
@@ -237,7 +237,7 @@ source code and documentation.
   - [mldsa/src/native/x86_64/src/pointwise_acc_l4.S](mldsa/src/native/x86_64/src/pointwise_acc_l4.S)
   - [mldsa/src/native/x86_64/src/pointwise_acc_l5.S](mldsa/src/native/x86_64/src/pointwise_acc_l5.S)
   - [mldsa/src/native/x86_64/src/pointwise_acc_l7.S](mldsa/src/native/x86_64/src/pointwise_acc_l7.S)
-  - [mldsa/src/native/x86_64/src/poly_caddq_avx2.c](mldsa/src/native/x86_64/src/poly_caddq_avx2.c)
+  - [mldsa/src/native/x86_64/src/poly_caddq_avx2.S](mldsa/src/native/x86_64/src/poly_caddq_avx2.S)
   - [mldsa/src/native/x86_64/src/poly_chknorm_avx2.c](mldsa/src/native/x86_64/src/poly_chknorm_avx2.c)
   - [mldsa/src/native/x86_64/src/poly_decompose_32_avx2.c](mldsa/src/native/x86_64/src/poly_decompose_32_avx2.c)
   - [mldsa/src/native/x86_64/src/poly_decompose_88_avx2.c](mldsa/src/native/x86_64/src/poly_decompose_88_avx2.c)
diff --git a/dev/x86_64/src/poly_caddq_avx2.c b/dev/x86_64/src/poly_caddq_avx2.S
similarity index 53%
rename from dev/x86_64/src/poly_caddq_avx2.c
rename to dev/x86_64/src/poly_caddq_avx2.S
index 05d86d14f..882424451 100644
--- a/dev/x86_64/src/poly_caddq_avx2.c
+++ b/dev/x86_64/src/poly_caddq_avx2.S
@@ -17,14 +17,6 @@
  * AVX2 Dilithium implementation @[REF_AVX2].
  */
 
-#include "../../../common.h"
-
-#if defined(MLD_ARITH_BACKEND_X86_64_DEFAULT) && \
-    !defined(MLD_CONFIG_MULTILEVEL_NO_SHARED)
-
-#include <immintrin.h>
-#include "arith_native_x86_64.h"
-#include "consts.h"
 
 /*************************************************
  * Name:        mld_poly_caddq_avx2
@@ -34,28 +26,45 @@
  *
  * Arguments:   - int32_t *r: pointer to input/output polynomial
  **************************************************/
-void mld_poly_caddq_avx2(int32_t *r)
-{
-  unsigned int i;
-  __m256i f, g;
-  const __m256i q = _mm256_set1_epi32(MLDSA_Q);
-  const __m256i zero = _mm256_setzero_si256();
-  __m256i *rr = (__m256i *)r;
-
-  for (i = 0; i < MLDSA_N / 8; i++)
-  {
-    f = _mm256_load_si256(&rr[i]);
-    g = _mm256_cmpgt_epi32(zero, f);
-    g = _mm256_and_si256(g, q);
-    f = _mm256_add_epi32(f, g);
-    _mm256_store_si256(&rr[i], f);
-  }
-}
-
-#else /* MLD_ARITH_BACKEND_X86_64_DEFAULT && !MLD_CONFIG_MULTILEVEL_NO_SHARED \
-       */
-
-MLD_EMPTY_CU(avx2_reduce)
-
-#endif /* !(MLD_ARITH_BACKEND_X86_64_DEFAULT && \
-          !MLD_CONFIG_MULTILEVEL_NO_SHARED) */
+
+#include "../../../common.h"
+
+#if defined(MLD_ARITH_BACKEND_X86_64_DEFAULT) && \
+    !defined(MLD_CONFIG_MULTILEVEL_NO_SHARED)
+
+/* simpasm: header-end */
+
+.macro caddq_vector offset, reg
+vpcmpgtd \offset(%rdi), %ymm2, \reg
+vpand   %ymm1, \reg, \reg
+vpaddd  \offset(%rdi), \reg, \reg
+vmovdqa  \reg, \offset(%rdi)
+.endm
+
+.text
+.global	MLD_ASM_NAMESPACE(poly_caddq_avx2)
+.balign 16
+MLD_ASM_FN_SYMBOL(poly_caddq_avx2)
+
+mov	$8380417, %edx
+leaq	1024(%rdi), %rax
+vpxor	%xmm2, %xmm2, %xmm2
+vmovd	%edx, %xmm1
+vpbroadcastd	%xmm1, %ymm1
+
+poly_caddq_avx2_loop:
+
+caddq_vector 0, %ymm0
+caddq_vector 32, %ymm3
+caddq_vector 64, %ymm4
+caddq_vector 96, %ymm5
+
+addq   $128, %rdi        /* advance by 128 bytes (4 vectors) */ 
+cmpq   %rdi, %rax
+jne    poly_caddq_avx2_loop   /* 8 iterations (32/4 = 8) */ 
+ret
+
+/* simpasm: footer-start */
+
+#endif /* MLD_ARITH_BACKEND_X86_64_DEFAULT && !MLD_CONFIG_MULTILEVEL_NO_SHARED \
+        */
diff --git a/mldsa/mldsa_native.c b/mldsa/mldsa_native.c
index e20a82f2c..9ad43f785 100644
--- a/mldsa/mldsa_native.c
+++ b/mldsa/mldsa_native.c
@@ -82,7 +82,6 @@
 #endif /* MLD_SYS_AARCH64 */
 #if defined(MLD_SYS_X86_64)
 #include "src/native/x86_64/src/consts.c"
-#include "src/native/x86_64/src/poly_caddq_avx2.c"
 #include "src/native/x86_64/src/poly_chknorm_avx2.c"
 #include "src/native/x86_64/src/poly_decompose_32_avx2.c"
 #include "src/native/x86_64/src/poly_decompose_88_avx2.c"
diff --git a/mldsa/mldsa_native_asm.S b/mldsa/mldsa_native_asm.S
index 36296bb5e..f0c54203f 100644
--- a/mldsa/mldsa_native_asm.S
+++ b/mldsa/mldsa_native_asm.S
@@ -86,6 +86,7 @@
 #include "src/native/x86_64/src/pointwise_acc_l4.S"
 #include "src/native/x86_64/src/pointwise_acc_l5.S"
 #include "src/native/x86_64/src/pointwise_acc_l7.S"
+#include "src/native/x86_64/src/poly_caddq_avx2.S"
 #endif /* MLD_SYS_X86_64 */
 #endif /* MLD_CONFIG_USE_NATIVE_BACKEND_ARITH */
 
diff --git a/mldsa/src/native/x86_64/src/poly_caddq_avx2.S b/mldsa/src/native/x86_64/src/poly_caddq_avx2.S
new file mode 100644
index 000000000..127dc7d01
--- /dev/null
+++ b/mldsa/src/native/x86_64/src/poly_caddq_avx2.S
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) The mldsa-native project authors
+ * SPDX-License-Identifier: Apache-2.0 OR ISC OR MIT
+ */
+
+/* References
+ * ==========
+ *
+ * - [REF_AVX2]
+ *   CRYSTALS-Dilithium optimized AVX2 implementation
+ *   Bai, Ducas, Kiltz, Lepoint, Lyubashevsky, Schwabe, Seiler, Stehlé
+ *   https://github.com/pq-crystals/dilithium/tree/master/avx2
+ */
+
+/*
+ * This file is derived from the public domain
+ * AVX2 Dilithium implementation @[REF_AVX2].
+ */
+
+
+/*************************************************
+ * Name:        mld_poly_caddq_avx2
+ *
+ * Description: For all coefficients of in/out polynomial add Q if
+ *              coefficient is negative.
+ *
+ * Arguments:   - int32_t *r: pointer to input/output polynomial
+ **************************************************/
+
+#include "../../../common.h"
+
+#if defined(MLD_ARITH_BACKEND_X86_64_DEFAULT) && \
+    !defined(MLD_CONFIG_MULTILEVEL_NO_SHARED)
+
+
+/*
+ * WARNING: This file is auto-derived from the mldsa-native source file
+ *   dev/x86_64/src/poly_caddq_avx2.S using scripts/simpasm. Do not modify it directly.
+ */
+
+#if defined(__ELF__)
+.section .note.GNU-stack,"",@progbits
+#endif
+
+.text
+.balign 4
+.global MLD_ASM_NAMESPACE(poly_caddq_avx2)
+MLD_ASM_FN_SYMBOL(poly_caddq_avx2)
+
+        .cfi_startproc
+        movl	$0x7fe001, %edx         # imm = 0x7FE001
+        leaq	0x400(%rdi), %rax
+        vpxor	%xmm2, %xmm2, %xmm2
+        vmovd	%edx, %xmm1
+        vpbroadcastd	%xmm1, %ymm1
+
+Lpoly_caddq_avx2_loop:
+        vpcmpgtd	(%rdi), %ymm2, %ymm0
+        vpand	%ymm1, %ymm0, %ymm0
+        vpaddd	(%rdi), %ymm0, %ymm0
+        vmovdqa	%ymm0, (%rdi)
+        vpcmpgtd	0x20(%rdi), %ymm2, %ymm3
+        vpand	%ymm1, %ymm3, %ymm3
+        vpaddd	0x20(%rdi), %ymm3, %ymm3
+        vmovdqa	%ymm3, 0x20(%rdi)
+        vpcmpgtd	0x40(%rdi), %ymm2, %ymm4
+        vpand	%ymm1, %ymm4, %ymm4
+        vpaddd	0x40(%rdi), %ymm4, %ymm4
+        vmovdqa	%ymm4, 0x40(%rdi)
+        vpcmpgtd	0x60(%rdi), %ymm2, %ymm5
+        vpand	%ymm1, %ymm5, %ymm5
+        vpaddd	0x60(%rdi), %ymm5, %ymm5
+        vmovdqa	%ymm5, 0x60(%rdi)
+        addq	$0x80, %rdi
+        cmpq	%rdi, %rax
+        jne	Lpoly_caddq_avx2_loop
+        retq
+        .cfi_endproc
+
+MLD_ASM_FN_SIZE(poly_caddq_avx2)
+
+
+#endif /* MLD_ARITH_BACKEND_X86_64_DEFAULT && !MLD_CONFIG_MULTILEVEL_NO_SHARED \
+        */
diff --git a/mldsa/src/native/x86_64/src/poly_caddq_avx2.c b/mldsa/src/native/x86_64/src/poly_caddq_avx2.c
deleted file mode 100644
index 05d86d14f..000000000
--- a/mldsa/src/native/x86_64/src/poly_caddq_avx2.c
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * Copyright (c) The mldsa-native project authors
- * SPDX-License-Identifier: Apache-2.0 OR ISC OR MIT
- */
-
-/* References
- * ==========
- *
- * - [REF_AVX2]
- *   CRYSTALS-Dilithium optimized AVX2 implementation
- *   Bai, Ducas, Kiltz, Lepoint, Lyubashevsky, Schwabe, Seiler, Stehlé
- *   https://github.com/pq-crystals/dilithium/tree/master/avx2
- */
-
-/*
- * This file is derived from the public domain
- * AVX2 Dilithium implementation @[REF_AVX2].
- */
-
-#include "../../../common.h"
-
-#if defined(MLD_ARITH_BACKEND_X86_64_DEFAULT) && \
-    !defined(MLD_CONFIG_MULTILEVEL_NO_SHARED)
-
-#include <immintrin.h>
-#include "arith_native_x86_64.h"
-#include "consts.h"
-
-/*************************************************
- * Name:        mld_poly_caddq_avx2
- *
- * Description: For all coefficients of in/out polynomial add Q if
- *              coefficient is negative.
- *
- * Arguments:   - int32_t *r: pointer to input/output polynomial
- **************************************************/
-void mld_poly_caddq_avx2(int32_t *r)
-{
-  unsigned int i;
-  __m256i f, g;
-  const __m256i q = _mm256_set1_epi32(MLDSA_Q);
-  const __m256i zero = _mm256_setzero_si256();
-  __m256i *rr = (__m256i *)r;
-
-  for (i = 0; i < MLDSA_N / 8; i++)
-  {
-    f = _mm256_load_si256(&rr[i]);
-    g = _mm256_cmpgt_epi32(zero, f);
-    g = _mm256_and_si256(g, q);
-    f = _mm256_add_epi32(f, g);
-    _mm256_store_si256(&rr[i], f);
-  }
-}
-
-#else /* MLD_ARITH_BACKEND_X86_64_DEFAULT && !MLD_CONFIG_MULTILEVEL_NO_SHARED \
-       */
-
-MLD_EMPTY_CU(avx2_reduce)
-
-#endif /* !(MLD_ARITH_BACKEND_X86_64_DEFAULT && \
-          !MLD_CONFIG_MULTILEVEL_NO_SHARED) */
diff --git a/test/bench/bench_components_mldsa.c b/test/bench/bench_components_mldsa.c
index fb83ddf82..6cf8627e5 100644
--- a/test/bench/bench_components_mldsa.c
+++ b/test/bench/bench_components_mldsa.c
@@ -84,6 +84,8 @@ static int bench(void)
   /* polyz_unpack */
   BENCH("polyz_unpack", mld_polyz_unpack(&poly_out, (const uint8_t *)data0))
 
+  BENCH("poly_caddq", mld_poly_caddq((mld_poly *)data0));
+
   return 0;
 }