From c40a2f5c6fa4e1773baef3e400a4a79cdc6ca1a6 Mon Sep 17 00:00:00 2001
From: Brad Nelson <flagxor@gmail.com>
Date: Sun, 3 Dec 2023 19:57:14 -0800
Subject: [PATCH] Adding initial pico-ice support.

---
 .gitmodules                    |  6 +++
 Makefile                       | 63 ++++++++++++++++++++++-
 esp32/allocation.fs            |  1 -
 pico-ice/CMakeLists.txt        | 43 ++++++++++++++++
 pico-ice/allocation.fs         | 18 +++++++
 pico-ice/autoboot.fs           | 16 ++++++
 pico-ice/builtins.h            | 91 ++++++++++++++++++++++++++++++++++
 pico-ice/main.c                | 62 +++++++++++++++++++++++
 pico-ice/pico-ice-sdk          |  1 +
 pico-ice/pico-sdk              |  1 +
 pico-ice/pico_sdk_import.cmake | 73 +++++++++++++++++++++++++++
 pico-ice/platform.fs           | 50 +++++++++++++++++++
 12 files changed, 422 insertions(+), 3 deletions(-)
 create mode 100644 .gitmodules
 create mode 100644 pico-ice/CMakeLists.txt
 create mode 100644 pico-ice/allocation.fs
 create mode 100644 pico-ice/autoboot.fs
 create mode 100644 pico-ice/builtins.h
 create mode 100644 pico-ice/main.c
 create mode 160000 pico-ice/pico-ice-sdk
 create mode 160000 pico-ice/pico-sdk
 create mode 100644 pico-ice/pico_sdk_import.cmake
 create mode 100644 pico-ice/platform.fs

diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..0c300cd
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "pico-ice/pico-sdk"]
+	path = pico-ice/pico-sdk
+	url = https://github.com/raspberrypi/pico-sdk
+[submodule "pico-ice/pico-ice-sdk"]
+	path = pico-ice/pico-ice-sdk
+	url = https://github.com/tinyvision-ai-inc/pico-ice-sdk
diff --git a/Makefile b/Makefile
index a48699c..f8495b3 100644
--- a/Makefile
+++ b/Makefile
@@ -26,6 +26,8 @@ POSIX = $(OUT)/posix
 WINDOWS = $(OUT)/windows
 ESP32 = $(OUT)/esp32
 ESP32_SIM = $(OUT)/esp32-sim
+PICO_ICE = $(OUT)/pico-ice
+PICO_ICE_SIM = $(OUT)/pico-ice-sim
 DEPLOY = $(OUT)/deploy
 
 OS = $(shell uname -s)
@@ -238,9 +240,9 @@ COMMON_PHASE1 = common/comments.fs \
                 common/structures.fs
 
 COMMON_PHASE1e = common/comments.fs \
-                                    common/tier2a_forth.fs \
+                 common/tier2a_forth.fs \
                  common/boot.fs \
-                                    common/tier2b_forth.fs \
+                 common/tier2b_forth.fs \
                  common/io.fs \
                  common/conditionals.fs \
                  common/vocabulary.fs \
@@ -287,6 +289,16 @@ WINDOWS_BOOT = $(COMMON_PHASE1) \
 $(GEN)/windows_boot.h: tools/source_to_string.js $(WINDOWS_BOOT) | $(GEN)
 	$< -win boot $(VERSION) $(REVISION) $(WINDOWS_BOOT) >$@
 
+PICO_ICE_BOOT =  $(COMMON_PHASE1) \
+                 pico-ice/allocation.fs \
+                 $(COMMON_PHASE2) \
+                 common/tasks.fs common/streams.fs \
+                 pico-ice/platform.fs \
+                 pico-ice/autoboot.fs \
+                 common/fini.fs
+$(GEN)/pico_ice_boot.h: tools/source_to_string.js $(PICO_ICE_BOOT) | $(GEN)
+	$< boot $(VERSION) $(REVISION) $(PICO_ICE_BOOT) >$@
+
 ESP32_BOOT = $(COMMON_PHASE1) \
              esp32/allocation.fs esp32/bindings.fs \
              $(COMMON_PHASE2) $(COMMON_FILETOOLS) \
@@ -793,6 +805,53 @@ CHIP_esp32cam=esp32
 %-build: $(ESP32)/%_build/ESP32forth.ino.bin
 	echo "done"
 
+# ---- PICO-ICE ----
+
+pico-ice: $(PICO_ICE)/ueforth_pico_ice.uf2
+
+$(PICO_ICE)/ueforth_pico_ice.uf2: \
+    $(PICO_ICE)/Makefile \
+    pico-ice/main.c \
+    pico-ice/builtins.h \
+    common/tier0_opcodes.h \
+    common/tier1_opcodes.h \
+    common/tier2_opcodes.h \
+    common/floats.h \
+    common/calls.h \
+    common/calling.h \
+    common/floats.h \
+    common/bits.h \
+    common/core.h \
+    common/interp.h \
+    $(GEN)/pico_ice_boot.h
+	make -C $(PICO_ICE) VERBOSE=1
+
+$(PICO_ICE)/Makefile:
+	cmake $(PICO_ICE) -S pico-ice -B $(PICO_ICE)
+
+# ---- PICO-ICE-SIM ----
+
+pico-ice-sim: $(PICO_ICE_SIM)/ueforth_pico_ice_sim
+
+$(PICO_ICE_SIM):
+	mkdir -p $@
+
+$(PICO_ICE_SIM)/ueforth_pico_ice_sim: \
+    pico-ice/main.c \
+    pico-ice/builtins.h \
+    common/tier0_opcodes.h \
+    common/tier1_opcodes.h \
+    common/tier2_opcodes.h \
+    common/floats.h \
+    common/calls.h \
+    common/calling.h \
+    common/floats.h \
+    common/bits.h \
+    common/core.h \
+    common/interp.h \
+    $(GEN)/pico_ice_boot.h | $(PICO_ICE_SIM)
+	$(CXX) $(CFLAGS) -DUEFORTH_SIM=1 $< -o $@
+
 # ---- PACKAGE ----
 
 $(ESP32)/ESP32forth.zip: \
diff --git a/esp32/allocation.fs b/esp32/allocation.fs
index 882b64e..449f541 100644
--- a/esp32/allocation.fs
+++ b/esp32/allocation.fs
@@ -16,4 +16,3 @@
 : allocate ( n -- a ior ) malloc dup 0= ;
 : free ( a -- ior ) sysfree 0 ;
 : resize ( a n -- a ior ) realloc dup 0= ;
-
diff --git a/pico-ice/CMakeLists.txt b/pico-ice/CMakeLists.txt
new file mode 100644
index 0000000..e072ce4
--- /dev/null
+++ b/pico-ice/CMakeLists.txt
@@ -0,0 +1,43 @@
+# Copyright 2024 Bradley D. Nelson
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+cmake_minimum_required(VERSION 3.13)
+
+# import the pico-sdk
+set(PICO_SDK_PATH ${CMAKE_CURRENT_SOURCE_DIR}/pico-sdk/)
+include(pico_sdk_import.cmake)
+
+# configure the pico-sdk project
+project(ueforth_pico_ice C CXX ASM)
+pico_sdk_init()
+
+# add the pico-ice-sdk
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/pico-ice-sdk)
+
+add_executable(${CMAKE_PROJECT_NAME} main.c)
+target_link_libraries(${CMAKE_PROJECT_NAME}
+    pico_ice_sdk
+    pico_stdio_usb
+)
+target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE
+   ${CMAKE_CURRENT_SOURCE_DIR}/../
+   ${CMAKE_CURRENT_SOURCE_DIR}/../out/
+)
+target_include_directories(${CMAKE_PROJECT_NAME} PUBLIC
+    ${CMAKE_CURRENT_LIST_DIR}
+    ${CMAKE_CURRENT_BINARY_DIR}
+)
+pico_add_extra_outputs(${CMAKE_PROJECT_NAME})
+pico_enable_stdio_usb(${CMAKE_PROJECT_NAME} 0)
+pico_enable_stdio_uart(${CMAKE_PROJECT_NAME} 0)
diff --git a/pico-ice/allocation.fs b/pico-ice/allocation.fs
new file mode 100644
index 0000000..455c698
--- /dev/null
+++ b/pico-ice/allocation.fs
@@ -0,0 +1,18 @@
+\ Copyright 2023 Bradley D. Nelson
+\
+\ Licensed under the Apache License, Version 2.0 (the "License");
+\ you may not use this file except in compliance with the License.
+\ You may obtain a copy of the License at
+\
+\     http://www.apache.org/licenses/LICENSE-2.0
+\
+\ Unless required by applicable law or agreed to in writing, software
+\ distributed under the License is distributed on an "AS IS" BASIS,
+\ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+\ See the License for the specific language governing permissions and
+\ limitations under the License.
+
+( Words with OS assist )
+: allocate ( n -- a ior ) malloc dup 0= ;
+: free ( a -- ior ) sysfree 0 ;
+: resize ( a n -- a ior ) realloc dup 0= ;
diff --git a/pico-ice/autoboot.fs b/pico-ice/autoboot.fs
new file mode 100644
index 0000000..7e758cf
--- /dev/null
+++ b/pico-ice/autoboot.fs
@@ -0,0 +1,16 @@
+\ Copyright 2023 Bradley D. Nelson
+\
+\ Licensed under the Apache License, Version 2.0 (the "License");
+\ you may not use this file except in compliance with the License.
+\ You may obtain a copy of the License at
+\
+\     http://www.apache.org/licenses/LICENSE-2.0
+\
+\ Unless required by applicable law or agreed to in writing, software
+\ distributed under the License is distributed on an "AS IS" BASIS,
+\ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+\ See the License for the specific language governing permissions and
+\ limitations under the License.
+
+( TODO: Add autoboot support. )
+' ok
diff --git a/pico-ice/builtins.h b/pico-ice/builtins.h
new file mode 100644
index 0000000..1386100
--- /dev/null
+++ b/pico-ice/builtins.h
@@ -0,0 +1,91 @@
+// Copyright 2023 Bradley D. Nelson
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifndef UEFORTH_SIM
+# include "pico/time.h"
+#endif
+
+// TODO: Implement RESIZE-FILE.
+// TODO: Implement FLUSH-FILE.
+
+#define PLATFORM_OPCODE_LIST \
+  REQUIRED_MEMORY_SUPPORT \
+  REQUIRED_SYSTEM_SUPPORT \
+  REQUIRED_FILES_SUPPORT \
+  CALLING_OPCODE_LIST \
+  FLOATING_POINT_LIST
+
+#define REQUIRED_MEMORY_SUPPORT \
+  YV(internals, MALLOC, SET malloc(n0)) \
+  YV(internals, SYSFREE, free(a0); DROP) \
+  YV(internals, REALLOC, SET realloc(a1, n0); NIP)
+
+#ifndef UEFORTH_SIM
+# define REQUIRED_SYSTEM_SUPPORT \
+  X("MS-TICKS", MS_TICKS, PUSH us_to_ms(get_absolute_time())) \
+  XV(internals, "RAW-YIELD", RAW_YIELD, tud_task()) \
+  XV(internals, "RAW-TERMINATE", RAW_TERMINATE, exit(n0); DROP) \
+  YV(internals, getchar_timeout_us, n0 = getchar_timeout_us(n0))
+#else
+# define REQUIRED_SYSTEM_SUPPORT \
+  X("MS-TICKS", MS_TICKS, PUSH (time(0) * 1000)) \
+  XV(internals, "RAW-YIELD", RAW_YIELD, sleep(0)) \
+  XV(internals, "RAW-TERMINATE", RAW_TERMINATE, exit(n0); DROP) \
+  YV(internals, getchar_timeout_us, DROP; PUSH fgetc(stdin))
+#endif
+
+#define REQUIRED_FILES_SUPPORT \
+  X("R/O", R_O, PUSH O_RDONLY) \
+  X("W/O", W_O, PUSH O_WRONLY) \
+  X("R/W", R_W, PUSH O_RDWR) \
+  Y(BIN, ) \
+  X("CLOSE-FILE", CLOSE_FILE, tos = close(tos); tos = tos ? errno : 0) \
+  X("OPEN-FILE", OPEN_FILE, cell_t mode = n0; DROP; cell_t len = n0; DROP; \
+    memcpy(filename, a0, len); filename[len] = 0; \
+    n0 = open(filename, mode, 0777); PUSH n0 < 0 ? errno : 0) \
+  X("CREATE-FILE", CREATE_FILE, cell_t mode = n0; DROP; cell_t len = n0; DROP; \
+    memcpy(filename, a0, len); filename[len] = 0; \
+    n0 = open(filename, mode | O_CREAT | O_TRUNC); PUSH n0 < 0 ? errno : 0) \
+  X("DELETE-FILE", DELETE_FILE, cell_t len = n0; DROP; \
+    memcpy(filename, a0, len); filename[len] = 0; \
+    n0 = unlink(filename); n0 = n0 ? errno : 0) \
+  X("RENAME-FILE", RENAME_FILE, \
+    cell_t len = n0; DROP; memcpy(filename, a0, len); filename[len] = 0; DROP; \
+    cell_t len2 = n0; DROP; memcpy(filename2, a0, len2); filename2[len2] = 0; \
+    n0 = rename(filename2, filename); n0 = n0 ? errno : 0) \
+  X("WRITE-FILE", WRITE_FILE, cell_t fd = n0; DROP; cell_t len = n0; DROP; \
+    n0 = write(fd, a0, len); n0 = n0 != len ? errno : 0) \
+  X("READ-FILE", READ_FILE, cell_t fd = n0; DROP; cell_t len = n0; DROP; \
+    n0 = read(fd, a0, len); PUSH n0 < 0 ? errno : 0) \
+  X("FILE-POSITION", FILE_POSITION, \
+    n0 = (cell_t) lseek(n0, 0, SEEK_CUR); PUSH n0 < 0 ? errno : 0) \
+  X("REPOSITION-FILE", REPOSITION_FILE, cell_t fd = n0; DROP; \
+    n0 = (cell_t) lseek(fd, tos, SEEK_SET); n0 = n0 < 0 ? errno : 0) \
+  X("FILE-SIZE", FILE_SIZE, struct stat st; w = fstat(n0, &st); \
+    n0 = (cell_t) st.st_size; PUSH w < 0 ? errno : 0) \
+  X("NON-BLOCK", NON_BLOCK, n0 = fcntl(n0, F_SETFL, O_NONBLOCK); \
+    n0 = n0 < 0 ? errno : 0)
+
+#define VOCABULARY_LIST V(forth) V(internals)
+
+#define PATH_MAX 256
+static char filename[PATH_MAX];
+static char filename2[PATH_MAX];
diff --git a/pico-ice/main.c b/pico-ice/main.c
new file mode 100644
index 0000000..203ebea
--- /dev/null
+++ b/pico-ice/main.c
@@ -0,0 +1,62 @@
+// Copyright 2023 Bradley D. Nelson
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdio.h>
+
+#ifndef UEFORTH_SIM
+# include "pico/stdlib.h"
+# include "boards/pico_ice.h"
+# include "tusb.h"
+#else
+# include <time.h>
+#endif
+
+#include "common/tier0_opcodes.h"
+#include "common/tier1_opcodes.h"
+#include "common/tier2_opcodes.h"
+#include "common/floats.h"
+#include "common/calls.h"
+
+#ifndef UEFORTH_SIM
+# define HEAP_SIZE (100 * 1024)
+#else
+# define HEAP_SIZE (200 * 1024)
+#endif
+#define STACK_CELLS (4 * 1024)
+
+#include "pico-ice/builtins.h"
+
+// TODO: Implement faults.
+#define FAULT_ENTRY
+static void forth_faults_setup(void) {
+}
+
+#include "common/bits.h"
+#include "common/core.h"
+#include "common/calling.h"
+#include "common/interp.h"
+#include "gen/pico_ice_boot.h"
+
+int main(int argc, char *argv[]) {
+#ifndef UEFORTH_SIM
+  tusb_init();
+  stdio_init_all();
+  tud_task();
+#endif
+
+  void *heap = malloc(HEAP_SIZE);
+  forth_init(argc, argv, heap, HEAP_SIZE, boot, sizeof(boot));
+  for (;;) { g_sys->rp = forth_run(g_sys->rp); }
+  return 1;
+}
diff --git a/pico-ice/pico-ice-sdk b/pico-ice/pico-ice-sdk
new file mode 160000
index 0000000..dfc0efe
--- /dev/null
+++ b/pico-ice/pico-ice-sdk
@@ -0,0 +1 @@
+Subproject commit dfc0efeb73a3a8bf8cfa9fac3f135b1f0ccf5bcb
diff --git a/pico-ice/pico-sdk b/pico-ice/pico-sdk
new file mode 160000
index 0000000..6a7db34
--- /dev/null
+++ b/pico-ice/pico-sdk
@@ -0,0 +1 @@
+Subproject commit 6a7db34ff63345a7badec79ebea3aaef1712f374
diff --git a/pico-ice/pico_sdk_import.cmake b/pico-ice/pico_sdk_import.cmake
new file mode 100644
index 0000000..65f8a6f
--- /dev/null
+++ b/pico-ice/pico_sdk_import.cmake
@@ -0,0 +1,73 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        # GIT_SUBMODULES_RECURSE was added in 3.17
+        if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+                    GIT_SUBMODULES_RECURSE FALSE
+            )
+        else ()
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+            )
+        endif ()
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            FetchContent_Populate(pico_sdk)
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})
diff --git a/pico-ice/platform.fs b/pico-ice/platform.fs
new file mode 100644
index 0000000..b1d74e9
--- /dev/null
+++ b/pico-ice/platform.fs
@@ -0,0 +1,50 @@
+\ Copyright 2023 Bradley D. Nelson
+\
+\ Licensed under the Apache License, Version 2.0 (the "License");
+\ you may not use this file except in compliance with the License.
+\ You may obtain a copy of the License at
+\
+\     http://www.apache.org/licenses/LICENSE-2.0
+\
+\ Unless required by applicable law or agreed to in writing, software
+\ distributed under the License is distributed on an "AS IS" BASIS,
+\ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+\ See the License for the specific language governing permissions and
+\ limitations under the License.
+
+( Add a yielding task so pause yields )
+internals definitions
+: yield-step   raw-yield yield ;
+' yield-step 100 100 task yield-task
+yield-task start-task
+forth definitions
+
+( Initial file handles )
+0 constant stdin
+1 constant stdout
+2 constant stderr
+
+( Set up Basic I/O )
+also internals definitions
+: setup-saving-base ;  ( TODO: implement. )
+variable last-key  -1 last-key !
+forth definitions internals
+: default-type ( a n -- ) stderr write-file throw ;
+: default-key? ( -- f )
+   last-key @ 0< if 1000 getchar_timeout_us last-key ! then
+   last-key @ 0< 0=
+;
+: default-key ( -- ch )
+   begin default-key? 0= while pause repeat
+   last-key @ -1 last-key !
+;
+previous
+
+' default-type is type
+' default-key is key
+' default-key? is key?
+' raw-terminate is terminate
+-1 echo !
+
+( Setup entry )
+internals : ok   ." uEforth" raw-ok ; forth