From fd6a03cc8d0479eb9c8349c3dee7dd2cd9573c3a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Remko=20Tron=C3=A7on?= <remko@el-tramo.be>
Date: Sun, 22 May 2022 16:56:39 +0200
Subject: [PATCH] getc->read

---
 src/waforth.wat    | 14 ++++++--------
 src/web/waforth.ts | 19 +++++++++++++------
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/src/waforth.wat b/src/waforth.wat
index a2bf2ef..e657999 100644
--- a/src/waforth.wat
+++ b/src/waforth.wat
@@ -13,7 +13,7 @@
 
   ;; I/O
   (import "shell" "emit" (func $shell_emit (param i32)))
-  (import "shell" "getc" (func $shell_getc (result i32)))
+  (import "shell" "read" (func $shell_read (param i32 i32) (result i32)))
   (import "shell" "key" (func $shell_key (result i32)))
 
   ;; Load a webassembly module.
@@ -77,6 +77,7 @@
   ;;
   ;; Memory layout:
   ;;   INPUT_BUFFER_BASE  :=   0x300
+  ;;   INPUT_BUFFER_SIZE  :=   0x700
   ;;   (Compiled modules are limited to 4096 bytes until Chrome refuses to load them synchronously)
   ;;   MODULE_HEADER_BASE :=  0x1000 
   ;;   RETURN_STACK_BASE  :=  0x2000
@@ -1730,13 +1731,10 @@
       (then
         (call $push (i32.const -1))
         (return)))
-    (block $endLoop (param i32) (result i32) 
-      (loop $loop (param i32) (result i32) 
-        (br_if $endLoop (i32.eq (local.tee $char (call $shell_getc)) (i32.const -1)))
-        (i32.store8 (i32.add (i32.const 0x300 (; = INPUT_BUFFER_BASE ;)) (global.get $inputBufferSize)) 
-                    (local.get $char))
-        (global.set $inputBufferSize (i32.add (global.get $inputBufferSize) (i32.const 1)))
-        (br $loop)))
+    (global.set $inputBufferSize 
+      (call $shell_read 
+        (i32.const 0x300 (; = INPUT_BUFFER_BASE ;)) 
+        (i32.const 0x700 (; = INPUT_BUFFER_SIZE ;))))
     (if (param i32) (result i32) (i32.eqz (global.get $inputBufferSize))
       (then (call $push (i32.const 0)))
       (else 
diff --git a/src/web/waforth.ts b/src/web/waforth.ts
index 72c51d6..ded122a 100644
--- a/src/web/waforth.ts
+++ b/src/web/waforth.ts
@@ -96,7 +96,7 @@ class WAForth {
   async load() {
     let table: WebAssembly.Table;
     let memory: WebAssembly.Memory;
-    const buffer = (this.#buffer = []);
+    this.#buffer = [];
 
     const instance = await WebAssembly.instantiate(wasmModule, {
       shell: {
@@ -110,11 +110,18 @@ class WAForth {
           }
         },
 
-        getc: () => {
-          if (buffer.length === 0) {
-            return -1;
+        read: (addr: number, length: number): number => {
+          let data = new Uint8Array(
+            (this.core!.exports.memory as WebAssembly.Memory).buffer,
+            addr,
+            length
+          );
+          let n = 0;
+          while (this.#buffer!.length > 0 && n < length) {
+            data[n] = this.#buffer!.shift()!;
+            n += 1;
           }
-          return buffer.pop();
+          return n;
         },
 
         key: () => {
@@ -212,7 +219,7 @@ class WAForth {
    */
   read(s: string) {
     const data = new TextEncoder().encode(s);
-    for (let i = data.length - 1; i >= 0; --i) {
+    for (let i = 0, len = data.length; i < len; ++i) {
       this.#buffer!.push(data[i]);
     }
   }