First commit

27 files changed, 1275 insertions, 0 deletions

diff --git a/src/interp/CMakeLists.txt b/src/interp/CMakeLists.txt
new file mode 100644
index 0000000..c38da8c
--- /dev/null
+++ b/src/interp/CMakeLists.txt
@@ -0,0 +1,21 @@
+# nanowasm, a tiny WebAssembly/Wasm interpreter
+# Copyright (C) 2023-2025  Xavier Del Campo Romero
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+target_sources(${PROJECT_NAME} PRIVATE
+    data_set.c
+    initexpr_set.c
+    ops.c
+    run.c
+    resume.c
+    start.c
+)
+
+add_subdirectory(global)
+add_subdirectory(linear)
+add_subdirectory(mem)
+add_subdirectory(routines)
+add_subdirectory(stack)
diff --git a/src/interp/data_set.c b/src/interp/data_set.c
new file mode 100644
index 0000000..266852b
--- /dev/null
+++ b/src/interp/data_set.c
@@ -0,0 +1,24 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/opcodes.h>
+
+static const enum opcode opcodes[] =
+{
+    OP_END,
+    OP_I32_CONST,
+};
+
+const struct nwp_interp_set nwp_interp_data_set =
+{
+    opcodes,
+    sizeof opcodes / sizeof *opcodes
+};
diff --git a/src/interp/global/CMakeLists.txt b/src/interp/global/CMakeLists.txt
new file mode 100644
index 0000000..0f0e056
--- /dev/null
+++ b/src/interp/global/CMakeLists.txt
@@ -0,0 +1,11 @@
+# nanowasm, a tiny WebAssembly/Wasm interpreter
+# Copyright (C) 2023-2025  Xavier Del Campo Romero
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+target_sources(${PROJECT_NAME} PRIVATE
+    load.c
+    store.c
+)
diff --git a/src/interp/global/load.c b/src/interp/global/load.c
new file mode 100644
index 0000000..26d8c8d
--- /dev/null
+++ b/src/interp/global/load.c
@@ -0,0 +1,34 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/global.h>
+#include <nw/mem.h>
+#include <nw/log.h>
+
+enum nw_state nwp_global_load(struct nw_interp *const i,
+    struct nw_sm_io *const io, const nw_varuint32 index)
+{
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const size_t offset = index * sizeof (struct nw_global);
+    const enum nw_state n = nwp_mem_load(&cfg->global, io, offset, cfg->user);
+
+    if (n == NW_FATAL)
+    {
+        static const char *const exc = "failed to load from global memory";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+    }
+
+    return n;
+}
diff --git a/src/interp/global/store.c b/src/interp/global/store.c
new file mode 100644
index 0000000..91550d4
--- /dev/null
+++ b/src/interp/global/store.c
@@ -0,0 +1,34 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/global.h>
+#include <nw/interp.h>
+#include <nw/mem.h>
+#include <nw/log.h>
+
+enum nw_state nwp_global_store(struct nw_interp *const i,
+    struct nw_sm_io *const io, const nw_varuint32 index)
+{
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const size_t offset = index * sizeof (struct nw_global);
+    const enum nw_state n = nwp_mem_store(&cfg->global, io, offset, cfg->user);
+
+    if (n == NW_FATAL)
+    {
+        static const char *const exc = "failed to store into global memory";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+    }
+
+    return n;
+}
diff --git a/src/interp/initexpr_set.c b/src/interp/initexpr_set.c
new file mode 100644
index 0000000..1e200f6
--- /dev/null
+++ b/src/interp/initexpr_set.c
@@ -0,0 +1,28 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/opcodes.h>
+
+static const enum opcode opcodes[] =
+{
+    OP_NOP,
+    OP_END,
+    OP_I32_CONST,
+    OP_I64_CONST,
+    OP_F32_CONST,
+    OP_F64_CONST
+};
+
+const struct nwp_interp_set nwp_interp_initexpr_set =
+{
+    opcodes,
+    sizeof opcodes / sizeof *opcodes
+};
diff --git a/src/interp/linear/CMakeLists.txt b/src/interp/linear/CMakeLists.txt
new file mode 100644
index 0000000..0f0e056
--- /dev/null
+++ b/src/interp/linear/CMakeLists.txt
@@ -0,0 +1,11 @@
+# nanowasm, a tiny WebAssembly/Wasm interpreter
+# Copyright (C) 2023-2025  Xavier Del Campo Romero
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+target_sources(${PROJECT_NAME} PRIVATE
+    load.c
+    store.c
+)
diff --git a/src/interp/linear/load.c b/src/interp/linear/load.c
new file mode 100644
index 0000000..afc6154
--- /dev/null
+++ b/src/interp/linear/load.c
@@ -0,0 +1,39 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nanowasm/linear.h>
+#include <nw/interp.h>
+#include <nw/mem.h>
+#include <nw/log.h>
+
+enum nw_state nwp_linear_load(struct nw_interp *const i,
+    struct nw_sm_io *const io, const unsigned long offset)
+{
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const enum nw_state n = nwp_mem_load(&cfg->linear, io, offset, cfg->user);
+
+    if (n == NW_FATAL)
+    {
+        static const char *const exc = "failed to load from linear memory";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+    }
+
+    return n;
+}
+
+enum nw_state nw_linear_load(struct nw_inst *const i,
+    struct nw_sm_io *const io, const unsigned long offset)
+{
+    return nwp_linear_load(&i->interp, io, offset);
+}
diff --git a/src/interp/linear/store.c b/src/interp/linear/store.c
new file mode 100644
index 0000000..6edffd9
--- /dev/null
+++ b/src/interp/linear/store.c
@@ -0,0 +1,40 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nanowasm/linear.h>
+#include <nw/linear.h>
+#include <nw/interp.h>
+#include <nw/mem.h>
+#include <nw/log.h>
+
+enum nw_state nwp_linear_store(struct nw_interp *const i,
+    struct nw_sm_io *const io, const unsigned long offset)
+{
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const enum nw_state n = nwp_mem_store(&cfg->linear, io, offset, cfg->user);
+
+    if (n == NW_FATAL)
+    {
+        static const char *const exc = "failed to store into linear memory";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+    }
+
+    return n;
+}
+
+enum nw_state nw_linear_store(struct nw_inst *const i,
+    struct nw_sm_io *const io, const unsigned long offset)
+{
+    return nwp_linear_store(&i->interp, io, offset);
+}
diff --git a/src/interp/mem/CMakeLists.txt b/src/interp/mem/CMakeLists.txt
new file mode 100644
index 0000000..0f0e056
--- /dev/null
+++ b/src/interp/mem/CMakeLists.txt
@@ -0,0 +1,11 @@
+# nanowasm, a tiny WebAssembly/Wasm interpreter
+# Copyright (C) 2023-2025  Xavier Del Campo Romero
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+target_sources(${PROJECT_NAME} PRIVATE
+    load.c
+    store.c
+)
diff --git a/src/interp/mem/load.c b/src/interp/mem/load.c
new file mode 100644
index 0000000..0ccf29b
--- /dev/null
+++ b/src/interp/mem/load.c
@@ -0,0 +1,27 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/mem.h>
+#include <nw/log.h>
+
+enum nw_state nwp_mem_load(const struct nw_mem_cfg *const cfg,
+    struct nw_sm_io *const io, const nw_varuint32 offset, void *const user)
+{
+    void *const dst = (unsigned char *)io->buf + io->read;
+    const int n = cfg->load(offset + io->read, dst, io->n - io->read, user);
+
+    if (n < 0)
+        return NW_FATAL;
+    else if ((io->read += n) >= io->n)
+        return NW_OK;
+
+    return NW_AGAIN;
+}
diff --git a/src/interp/mem/store.c b/src/interp/mem/store.c
new file mode 100644
index 0000000..cc58169
--- /dev/null
+++ b/src/interp/mem/store.c
@@ -0,0 +1,27 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/mem.h>
+#include <nw/log.h>
+
+enum nw_state nwp_mem_store(const struct nw_mem_cfg *const cfg,
+    struct nw_sm_io *const io, const nw_varuint32 offset, void *const user)
+{
+    const void *const src = (const unsigned char *)io->buf + io->read;
+    const int n = cfg->store(offset + io->read, src, io->n - io->read, user);
+
+    if (n < 0)
+        return NW_FATAL;
+    else if ((io->read += n) >= io->n)
+        return NW_OK;
+
+    return NW_AGAIN;
+}
diff --git a/src/interp/ops.c b/src/interp/ops.c
new file mode 100644
index 0000000..6135f96
--- /dev/null
+++ b/src/interp/ops.c
@@ -0,0 +1,278 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/opcodes.h>
+#include <nw/ops.h>
+#include <nw/interp.h>
+
+static void (*const ops[])(struct nw_interp *) =
+{
+    nwp_op_unreachable, /* OP_UNREACHABLE */
+    nwp_op_nop, /* OP_NOP */
+    nwp_op_block, /* OP_BLOCK */
+    nwp_op_loop, /* OP_LOOP */
+    NULL, /* OP_IF */
+    NULL, /* OP_ELSE */
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    nwp_op_end, /* OP_END */
+    nwp_op_br, /* OP_BR */
+    nwp_op_br_if, /* OP_BR_IF */
+    NULL, /* OP_BR_TABLE */
+    nwp_op_return, /* OP_RETURN */
+    nwp_op_call, /* OP_CALL */
+    nwp_op_call_indirect, /* OP_CALL_INDIRECT */
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    nwp_op_drop, /* OP_DROP */
+    NULL, /* OP_SELECT */
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    nwp_op_get_local, /* OP_GET_LOCAL */
+    nwp_op_set_local, /* OP_SET_LOCAL */
+    nwp_op_tee_local, /* OP_TEE_LOCAL */
+    nwp_op_get_global, /* OP_GET_GLOBAL */
+    nwp_op_set_global, /* OP_SET_GLOBAL */
+    NULL,
+    NULL,
+    NULL,
+    nwp_op_i32_load, /* OP_I32_LOAD */
+    NULL, /* OP_I64_LOAD */
+    NULL, /* OP_F32_LOAD */
+    NULL, /* OP_F64_LOAD */
+    NULL, /* OP_I32_LOAD8_S */
+    nwp_op_i32_load8_u, /* OP_I32_LOAD8_U */
+    NULL, /* OP_I32_LOAD16_S */
+    NULL, /* OP_I32_LOAD16_U */
+    NULL, /* OP_I64_LOAD8_S */
+    NULL, /* OP_I64_LOAD8_U */
+    NULL, /* OP_I64_LOAD16_S */
+    NULL, /* OP_I64_LOAD16_U */
+    NULL, /* OP_I64_LOAD32_S */
+    NULL, /* OP_I64_LOAD32_U */
+    nwp_op_i32_store, /* OP_I32_STORE */
+    nwp_op_i64_store, /* OP_I64_STORE */
+    NULL, /* OP_F32_STORE */
+    NULL, /* OP_F64_STORE */
+    NULL, /* OP_I32_STORE8 */
+    NULL, /* OP_I32_STORE16 */
+    NULL, /* OP_I64_STORE8 */
+    NULL, /* OP_I64_STORE16 */
+    NULL, /* OP_I64_STORE32 */
+    NULL, /* OP_CURRENT_MEMORY */
+    NULL, /* OP_GROW_MEMORY */
+    nwp_op_i32_const, /* OP_I32_CONST */
+    nwp_op_i64_const, /* OP_I64_CONST */
+    NULL, /* OP_F32_CONST */
+    NULL, /* OP_F64_CONST */
+    nwp_op_i32_eqz, /* OP_I32_EQZ */
+    nwp_op_i32_eq, /* OP_I32_EQ */
+    nwp_op_i32_ne, /* OP_I32_NE */
+    nwp_op_i32_lt_s, /* OP_I32_LT_S */
+    NULL, /* OP_I32_LT_U */
+    NULL, /* OP_I32_GT_S */
+    NULL, /* OP_I32_GT_U */
+    NULL, /* OP_I32_LE_S */
+    NULL, /* OP_I32_LE_U */
+    nwp_op_i32_ge_s, /* OP_I32_GE_S */
+    nwp_op_i32_ge_u, /* OP_I32_GE_U */
+    NULL, /* OP_I64_EQZ */
+    NULL, /* OP_I64_EQ */
+    NULL, /* OP_I64_NE */
+    NULL, /* OP_I64_LT_S */
+    NULL, /* OP_I64_LT_U */
+    NULL, /* OP_I64_GT_S */
+    NULL, /* OP_I64_GT_U */
+    NULL, /* OP_I64_LE_S */
+    NULL, /* OP_I64_LE_U */
+    NULL, /* OP_I64_GE_S */
+    NULL, /* OP_I64_GE_U */
+    NULL, /* OP_F32_EQ */
+    NULL, /* OP_F32_NE */
+    NULL, /* OP_F32_LT */
+    NULL, /* OP_F32_GT */
+    NULL, /* OP_F32_LE */
+    NULL, /* OP_F32_GE */
+    NULL, /* OP_F64_EQ */
+    NULL, /* OP_F64_NE */
+    NULL, /* OP_F64_LT */
+    NULL, /* OP_F64_GT */
+    NULL, /* OP_F64_LE */
+    NULL, /* OP_F64_GE */
+    NULL, /* OP_I32_CLZ */
+    NULL, /* OP_I32_CTZ */
+    NULL, /* OP_I32_POPCNT */
+    nwp_op_i32_add, /* OP_I32_ADD */
+    nwp_op_i32_sub, /* OP_I32_SUB */
+    nwp_op_i32_mul, /* OP_I32_MUL */
+    NULL, /* OP_I32_DIV_S */
+    NULL, /* OP_I32_DIV_U */
+    NULL, /* OP_I32_REM_S */
+    NULL, /* OP_I32_REM_U */
+    nwp_op_i32_and, /* OP_I32_AND */
+    nwp_op_i32_or, /* OP_I32_OR */
+    NULL, /* OP_I32_XOR */
+    NULL, /* OP_I32_SHL */
+    NULL, /* OP_I32_SHR_S */
+    NULL, /* OP_I32_SHR_U */
+    NULL, /* OP_I32_ROTL */
+    NULL, /* OP_I32_ROTR */
+    NULL, /* OP_I64_CLZ */
+    NULL, /* OP_I64_CTZ */
+    NULL, /* OP_I64_POPCNT */
+    NULL, /* OP_I64_ADD */
+    NULL, /* OP_I64_SUB */
+    NULL, /* OP_I64_MUL */
+    NULL, /* OP_I64_DIV_S */
+    NULL, /* OP_I64_DIV_U */
+    NULL, /* OP_I64_REM_S */
+    NULL, /* OP_I64_REM_U */
+    NULL, /* OP_I64_AND */
+    NULL, /* OP_I64_OR */
+    NULL, /* OP_I64_XOR */
+    NULL, /* OP_I64_SHL */
+    NULL, /* OP_I64_SHR_S */
+    NULL, /* OP_I64_SHR_U */
+    NULL, /* OP_I64_ROTL */
+    NULL, /* OP_I64_ROTR */
+    NULL, /* OP_F32_ABS */
+    NULL, /* OP_F32_NEG */
+    NULL, /* OP_F32_CEIL */
+    NULL, /* OP_F32_FLOOR */
+    NULL, /* OP_F32_TRUNC */
+    NULL, /* OP_F32_NEAREST */
+    NULL, /* OP_F32_SQRT */
+    NULL, /* OP_F32_ADD */
+    NULL, /* OP_F32_SUB */
+    NULL, /* OP_F32_MUL */
+    NULL, /* OP_F32_DIV */
+    NULL, /* OP_F32_MIN */
+    NULL, /* OP_F32_MAX */
+    NULL, /* OP_F32_COPYSIGN */
+    NULL, /* OP_F64_ABS */
+    NULL, /* OP_F64_NEG */
+    NULL, /* OP_F64_CEIL */
+    NULL, /* OP_F64_FLOOR */
+    NULL, /* OP_F64_TRUNC */
+    NULL, /* OP_F64_NEAREST */
+    NULL, /* OP_F64_SQRT */
+    NULL, /* OP_F64_ADD */
+    NULL, /* OP_F64_SUB */
+    NULL, /* OP_F64_MUL */
+    NULL, /* OP_F64_DIV */
+    NULL, /* OP_F64_MIN */
+    NULL, /* OP_F64_MAX */
+    NULL, /* OP_F64_COPYSIGN */
+    NULL, /* OP_I32_WRAP_I64 */
+    NULL, /* OP_I32_TRUNC_S_F32 */
+    NULL, /* OP_I32_TRUNC_U_F32 */
+    NULL, /* OP_I32_TRUNC_S_F64 */
+    NULL, /* OP_I32_TRUNC_U_F64 */
+    NULL, /* OP_I64_EXTEND_S_I32 */
+    NULL, /* OP_I64_EXTEND_U_I32 */
+    NULL, /* OP_I64_TRUNC_S_F32 */
+    NULL, /* OP_I64_TRUNC_U_F32 */
+    NULL, /* OP_I64_TRUNC_S_F64 */
+    NULL, /* OP_I64_TRUNC_U_F64 */
+    NULL, /* OP_F32_CONVERT_S_I32 */
+    NULL, /* OP_F32_CONVERT_U_I32 */
+    NULL, /* OP_F32_CONVERT_S_I64 */
+    NULL, /* OP_F32_CONVERT_U_I64 */
+    NULL, /* OP_F32_DEMOTE_F64 */
+    NULL, /* OP_F64_CONVERT_S_I32 */
+    NULL, /* OP_F64_CONVERT_U_I32 */
+    NULL, /* OP_F64_CONVERT_S_I64 */
+    NULL, /* OP_F64_CONVERT_U_I64 */
+    NULL, /* OP_F64_PROMOTE_F32 */
+    NULL, /* OP_I32_REINTERPRET_F32 */
+    NULL, /* OP_I64_REINTERPRET_F64 */
+    NULL, /* OP_F32_REINTERPRET_I32 */
+    NULL, /* OP_F64_REINTERPRET_I64 */
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL /* OP_MISC */
+};
+
+const struct nwp_ops nwp_ops =
+{
+    ops,
+    sizeof ops / sizeof *ops
+};
diff --git a/src/interp/resume.c b/src/interp/resume.c
new file mode 100644
index 0000000..cf9ece2
--- /dev/null
+++ b/src/interp/resume.c
@@ -0,0 +1,20 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nanowasm/types.h>
+#include <nw/interp.h>
+
+void nwp_interp_resume(struct nw_interp *const i)
+{
+    if (i->set)
+        nwp_interp_limited(i);
+    else
+        nwp_interp_full(i);
+}
diff --git a/src/interp/routines/CMakeLists.txt b/src/interp/routines/CMakeLists.txt
new file mode 100644
index 0000000..b27172b
--- /dev/null
+++ b/src/interp/routines/CMakeLists.txt
@@ -0,0 +1,13 @@
+# nanowasm, a tiny WebAssembly/Wasm interpreter
+# Copyright (C) 2023-2025  Xavier Del Campo Romero
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+target_sources(${PROJECT_NAME} PRIVATE
+    execute.c
+    find_export.c
+    full.c
+    limited.c
+)
diff --git a/src/interp/routines/execute.c b/src/interp/routines/execute.c
new file mode 100644
index 0000000..49711ae
--- /dev/null
+++ b/src/interp/routines/execute.c
@@ -0,0 +1,83 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nw/interp.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/opcodes.h>
+#include <nw/ops.h>
+#include <nw/routines.h>
+
+static enum nw_state execute(struct nw_interp *const i)
+{
+    struct nw_i_sm_b *const b = &i->sm.bytecode;
+
+#ifdef NW_LOG
+    nwp_log("opcode: %s, pc=%#lx\n", nwp_op_tostr(b->op), b->pc);
+#endif
+    b->f(i);
+    i->fr.prev_op = b->op;
+    return NW_AGAIN;
+}
+
+static enum nw_state repeat(struct nw_interp *const i)
+{
+    struct nw_i_sm_b *const b = &i->sm.bytecode;
+    struct nw_next *const next = &b->next;
+    const enum nw_state n = next->fn(next->user, next);
+
+    if (n)
+        return n;
+
+    return execute(i);
+}
+
+static enum nw_state exec_pc(struct nw_interp *const i)
+{
+    struct nw_i_sm_b *const b = &i->sm.bytecode;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const long pc = b->pc;
+
+    if (cfg->pc)
+    {
+        const enum nw_state n = cfg->pc(pc, &b->next, cfg->user);
+
+        if (n == NW_FATAL)
+        {
+            static const char *const exc = "pc callback failed";
+
+            i->exception = exc;
+#ifdef NW_LOG
+            nwp_log("%s, pc: %ld\n", exc, pc);
+#endif
+            return NW_FATAL;
+        }
+        else if (n)
+        {
+            i->next = repeat;
+            return n;
+        }
+    }
+
+    return execute(i);
+}
+
+enum nw_state nwp_execute(struct nw_interp *const i)
+{
+    struct nw_i_sm_b *const b = &i->sm.bytecode;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = cfg->tell(&b->pc, cfg->user);
+
+    if (n)
+        return n;
+
+    b->pc -= sizeof b->op;
+    i->next = exec_pc;
+    return NW_AGAIN;
+}
diff --git a/src/interp/routines/find_export.c b/src/interp/routines/find_export.c
new file mode 100644
index 0000000..effa8d1
--- /dev/null
+++ b/src/interp/routines/find_export.c
@@ -0,0 +1,229 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nanowasm/types.h>
+#include <nw/interp.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/routines.h>
+#include <string.h>
+
+static enum nw_state entry_loop(struct nw_interp *i);
+
+static enum nw_state get_index(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &e->index, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = e->next;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_kind(struct nw_interp *const i)
+{
+    unsigned char kind;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_io io = {0};
+    enum nw_state n;
+
+    io.buf = &kind;
+    io.n = sizeof kind;
+
+    if ((n = nwp_io_read(cfg, &io, cfg->user)))
+        return n;
+    else if (kind >= NW_KINDS)
+    {
+        static const char *const exc = "invalid export kind";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %#x\n", exc, (unsigned)kind);
+#endif
+        return NW_FATAL;
+    }
+
+    e->kind = kind;
+    i->next = get_index;
+    return NW_AGAIN;
+}
+
+static enum nw_state skip_index(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    nw_varuint32 index;
+    const enum nw_state n = nwp_varuint32(cfg, l, &index, cfg->user);
+
+    if (n)
+        return n;
+
+    e->entry_i++;
+    i->next = entry_loop;
+    return NW_AGAIN;
+}
+
+static enum nw_state skip_kind(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    unsigned char b;
+    struct nw_sm_io io = {0};
+    enum nw_state n;
+
+    io.buf = &b;
+    io.n = sizeof b;
+
+    if ((n = nwp_io_read(cfg, &io, cfg->user)))
+        return n;
+
+    i->next = skip_index;
+    return NW_AGAIN;
+}
+
+static enum nw_state skip_field_str(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const struct nw_i_sm_exp *const e = &i->sm.export;
+    const long offset = e->offset + (e->len - e->len_i);
+    const enum nw_state n = cfg->seek(offset, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = skip_kind;
+    return NW_AGAIN;
+}
+
+static enum nw_state tell(struct nw_interp *const i)
+{
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = cfg->tell(&e->offset, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = skip_field_str;
+    return NW_AGAIN;
+}
+
+static enum nw_state compare(struct nw_interp *const i)
+{
+    unsigned char b;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_io io = {0};
+    enum nw_state n;
+
+    io.buf = &b;
+    io.n = sizeof b;
+
+    if ((n = nwp_io_read(cfg, &io, cfg->user)))
+        return n;
+    else if (b != e->sym[e->len_i++])
+        i->next = tell;
+    else if (e->len_i >= e->len)
+        i->next = get_kind;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state get_len(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &e->len, cfg->user);
+
+    if (n)
+        return n;
+    else if (e->len != strlen(e->sym))
+        i->next = skip_field_str;
+    else
+        i->next = compare;
+
+    return NW_AGAIN;
+}
+
+static enum nw_state entry_loop(struct nw_interp *const i)
+{
+    struct nw_i_sm_exp *const e = &i->sm.export;
+
+    if (e->entry_i >= e->count)
+    {
+        static const char *const exc = "failed to find symbol";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %s\n", exc, e->sym);
+#endif
+        return NW_FATAL;
+    }
+
+    e->len_i = 0;
+    i->next = get_len;
+    return NW_AGAIN;
+}
+
+static enum nw_state get_count(struct nw_interp *const i)
+{
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    struct nw_i_sm_exp *const e = &i->sm.export;
+    struct nw_sm_leb128 *const l = &e->leb128;
+    const enum nw_state n = nwp_varuint32(cfg, l, &e->count, cfg->user);
+
+    if (n)
+        return n;
+
+    i->next = entry_loop;
+    return NW_AGAIN;
+}
+
+static enum nw_state seek(struct nw_interp *const i)
+{
+    const struct nw_mod *const m = i->cfg.m;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const long offset = m->sections[NW_SECTION_EXPORT];
+    enum nw_state n;
+
+    if (!offset)
+    {
+        static const char *const exc = "section not found";
+
+        i->exception = exc;
+#ifdef NW_LOG
+        nwp_log("%s: %s\n", exc, "export");
+#endif
+        return NW_FATAL;
+    }
+    else if ((n = cfg->seek(offset, cfg->user)))
+        return n;
+
+    i->next = get_count;
+    return NW_AGAIN;
+}
+
+void nwp_find_export(struct nw_interp *const i, const char *const sym,
+    enum nw_state (*const next)(struct nw_interp *))
+{
+    const struct nw_i_sm_exp e = {0};
+    struct nw_i_sm_exp *const pe = &i->sm.export;
+
+    *pe = e;
+    pe->sym = sym;
+    pe->next = next;
+    i->next = seek;
+}
diff --git a/src/interp/routines/full.c b/src/interp/routines/full.c
new file mode 100644
index 0000000..c00f11f
--- /dev/null
+++ b/src/interp/routines/full.c
@@ -0,0 +1,63 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nw/interp.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/opcodes.h>
+#include <nw/ops.h>
+#include <nw/routines.h>
+
+static enum nw_state tell(struct nw_interp *const i)
+{
+    long offset;
+    struct nw_i_sm_b *const b = &i->sm.bytecode;
+    static const char *const exc = "invalid opcode";
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = cfg->tell(&offset, cfg->user);
+
+    if (n)
+        return n;
+
+    offset -= sizeof b->op;
+
+#ifdef NW_LOG
+    nwp_log("%s: %#x, offset=%#lx\n", exc, (unsigned)b->op, offset);
+#endif
+    i->exception = exc;
+    return NW_FATAL;
+}
+
+static enum nw_state get_bytecode(struct nw_interp *const i)
+{
+    struct nw_i_sm_b *const b = &i->sm.bytecode;
+    const struct nw_io_cfg *const cfg = &i->cfg.io;
+    const enum nw_state n = nwp_io_read(cfg, &b->io, cfg->user);
+
+    if (n)
+        return n;
+    else if (b->op >= nwp_ops.n || !(b->f = nwp_ops.ops[b->op]))
+    {
+        i->next = tell;
+        return NW_AGAIN;
+    }
+
+    i->next = nwp_execute;
+    return NW_AGAIN;
+}
+
+void nwp_interp_full(struct nw_interp *const i)
+{
+    struct nw_i_sm_b *const pb = &i->sm.bytecode, b = {0};
+
+    b.io.buf = &pb->op;
+    b.io.n = sizeof pb->op;
+    *pb = b;
+    i->next = get_bytecode;
+}
diff --git a/src/interp/routines/limited.c b/src/interp/routines/limited.c
new file mode 100644
index 0000000..dc18ded
--- /dev/null
+++ b/src/interp/routines/limited.c
@@ -0,0 +1,54 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nanowasm/types.h>
+#include <nw/interp.h>
+#include <nw/io.h>
+#include <nw/log.h>
+#include <nw/routines.h>
+#include <stddef.h>
+
+static enum nw_state get_bytecode(struct nw_interp *const in)
+{
+    const struct nw_io_cfg *const cfg = &in->cfg.io;
+    struct nw_i_sm_b *const b = &in->sm.bytecode;
+    const struct nwp_interp_set *const set = in->set;
+    static const char *const exc = "invalid opcode";
+    const enum nw_state n = nwp_io_read(cfg, &b->io, cfg->user);
+    size_t i;
+
+    if (n)
+        return n;
+
+    for (i = 0; i < set->n; i++)
+        if (b->op == set->opcodes[i])
+        {
+            b->f = nwp_ops.ops[b->op];
+            in->next = nwp_execute;
+            return NW_AGAIN;
+        }
+
+#ifdef NW_LOG
+    nwp_log("%s: %#x\n", exc, (unsigned)b->op);
+#endif
+    in->exception = exc;
+    return NW_FATAL;
+}
+
+void nwp_interp_limited(struct nw_interp *const i)
+{
+    struct nw_i_sm_b *const b = &i->sm.bytecode;
+    struct nw_sm_io io = {0};
+
+    io.buf = &b->op;
+    io.n = sizeof b->op;
+    b->io = io;
+    i->next = get_bytecode;
+}
diff --git a/src/interp/run.c b/src/interp/run.c
new file mode 100644
index 0000000..f5e80e6
--- /dev/null
+++ b/src/interp/run.c
@@ -0,0 +1,16 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+
+enum nw_state nwp_interp_run(struct nw_interp *const i)
+{
+    return i->next(i);
+}
diff --git a/src/interp/stack/CMakeLists.txt b/src/interp/stack/CMakeLists.txt
new file mode 100644
index 0000000..51c7cb5
--- /dev/null
+++ b/src/interp/stack/CMakeLists.txt
@@ -0,0 +1,14 @@
+# nanowasm, a tiny WebAssembly/Wasm interpreter
+# Copyright (C) 2023-2025  Xavier Del Campo Romero
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+target_sources(${PROJECT_NAME} PRIVATE
+    pop.c
+    push.c
+    ptr.c
+    read.c
+    write.c
+)
diff --git a/src/interp/stack/pop.c b/src/interp/stack/pop.c
new file mode 100644
index 0000000..03ed689
--- /dev/null
+++ b/src/interp/stack/pop.c
@@ -0,0 +1,37 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/log.h>
+#include <nw/stack.h>
+
+enum nw_state nwp_stack_pop(struct nw_interp *const i,
+    struct nw_sm_io *const io)
+{
+    void *const dst = (unsigned char *)io->buf + io->read;
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const struct nw_fifo_cfg *const fc = &cfg->stack;
+    const int n = fc->pop(dst, io->n - io->read, cfg->user);
+
+    if (n < 0)
+    {
+        static const char *const exc = "failed to pop from stack";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+        return NW_FATAL;
+    }
+    else if ((io->read += n) >= io->n)
+        return NW_OK;
+
+    return NW_AGAIN;
+}
diff --git a/src/interp/stack/ptr.c b/src/interp/stack/ptr.c
new file mode 100644
index 0000000..d5fa455
--- /dev/null
+++ b/src/interp/stack/ptr.c
@@ -0,0 +1,21 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/stack.h>
+#include <stddef.h>
+
+size_t nwp_stack_ptr(const struct nw_interp *const i)
+{
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const struct nw_fifo_cfg *const fc = &cfg->stack;
+
+    return fc->ptr(cfg->user);
+}
diff --git a/src/interp/stack/push.c b/src/interp/stack/push.c
new file mode 100644
index 0000000..b8b48ce
--- /dev/null
+++ b/src/interp/stack/push.c
@@ -0,0 +1,37 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/log.h>
+#include <nw/stack.h>
+
+enum nw_state nwp_stack_push(struct nw_interp *const i,
+    struct nw_sm_io *const io)
+{
+    const void *const src = (const unsigned char *)io->buf + io->read;
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const struct nw_fifo_cfg *const fc = &cfg->stack;
+    const int n = fc->push(src, io->n - io->read, cfg->user);
+
+    if (n < 0)
+    {
+        static const char *const exc = "failed to push to stack";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+        return NW_FATAL;
+    }
+    else if ((io->read += n) >= io->n)
+        return NW_OK;
+
+    return NW_AGAIN;
+}
diff --git a/src/interp/stack/read.c b/src/interp/stack/read.c
new file mode 100644
index 0000000..8db6bcc
--- /dev/null
+++ b/src/interp/stack/read.c
@@ -0,0 +1,37 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/log.h>
+#include <nw/stack.h>
+
+enum nw_state nwp_stack_read(struct nw_interp *const i,
+    struct nw_sm_io *const io, const size_t offset)
+{
+    void *const dst = (unsigned char *)io->buf + io->read;
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const struct nw_fifo_cfg *const fc = &cfg->stack;
+    const int n = fc->read(offset + io->read, dst, io->n - io->read, cfg->user);
+
+    if (n < 0)
+    {
+        static const char *const exc = "failed to read from stack";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+        return NW_FATAL;
+    }
+    else if ((io->read += n) >= io->n)
+        return NW_OK;
+
+    return NW_AGAIN;
+}
diff --git a/src/interp/stack/write.c b/src/interp/stack/write.c
new file mode 100644
index 0000000..73e749e
--- /dev/null
+++ b/src/interp/stack/write.c
@@ -0,0 +1,38 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nw/interp.h>
+#include <nw/log.h>
+#include <nw/stack.h>
+
+enum nw_state nwp_stack_write(struct nw_interp *const i,
+    struct nw_sm_io *const io, const size_t offset)
+{
+    const void *const src = (const unsigned char *)io->buf + io->read;
+    const struct nw_interp_cfg *const cfg = &i->cfg;
+    const struct nw_fifo_cfg *const fc = &cfg->stack;
+    const int n = fc->write(offset + io->read, src, io->n - io->read,
+        cfg->user);
+
+    if (n < 0)
+    {
+        static const char *const exc = "failed to write to stack";
+
+#ifdef NW_LOG
+        nwp_log("%s\n", exc);
+#endif
+        i->exception = exc;
+        return NW_FATAL;
+    }
+    else if ((io->read += n) >= io->n)
+        return NW_OK;
+
+    return NW_AGAIN;
+}
diff --git a/src/interp/start.c b/src/interp/start.c
new file mode 100644
index 0000000..2bade41
--- /dev/null
+++ b/src/interp/start.c
@@ -0,0 +1,28 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2025  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nanowasm/nw.h>
+#include <nanowasm/types.h>
+#include <nw/interp.h>
+
+int nwp_interp_start(struct nw_interp *const i,
+    const struct nw_interp_cfg *const cfg,
+    const struct nwp_interp_set *const set)
+{
+    const struct nw_interp in = {0};
+    const struct nw_mod_out *const mout = &cfg->m->out;
+
+    *i = in;
+    i->cfg = *cfg;
+    i->set = set;
+    i->table.n_pages = mout->table.initial;
+    i->linear.n_pages = mout->linear.initial;
+    nwp_interp_resume(i);
+    return 0;
+}