Merge pull request ggerganov#2 from hodlen/fix/axpy_q4

support axpy q4_0 for loop

ggml-quants.c

@@ -2430,7 +2430,7 @@ void ggml_axpy_q4_0_q8_0(const int n, const void * restrict vx, const void * res
     assert(nb % 2 == 0);
 
     const block_q4_0 * restrict x = vx;
-
+#if defined(__AVX2__)
     // Initialize accumulator with zeros
     __m256 acc = _mm256_setzero_ps();
 
@@ -2491,7 +2491,21 @@ void ggml_axpy_q4_0_q8_0(const int n, const void * restrict vx, const void * res
         _mm256_storeu_ps((__m256*)(vz + i*128+96), by);
 
     }
+#else
+    float *res = (float *)vz;
+    float scale_fp32 = GGML_FP16_TO_FP32(scale);
+    for (int i = 0; i < nb; i++) {
+        float result_scale = GGML_FP16_TO_FP32(x[i].d) * scale_fp32;
+        int offset = i * QK4_0;
 
+        for (int j = 0; j < qk/2; ++j) {
+            const int v0 = (x[i].qs[j] & 0x0F) - 8;
+            const int v1 = (x[i].qs[j] >>   4) - 8;
+            res[offset + j] = res[offset + j] + ((float)(v0 * (int)alpha) * result_scale);
+            res[offset + j + qk/2] = res[offset + j + qk/2] + ((float)(v1 * (int)alpha) * result_scale);
+        }
+    }
+#endif
 }