Documentation and minor tweak to allocation size limit

coder-mike · Jul 2, 2022 · 3f8a47a · 3f8a47a
1 parent 9dd9718
commit 3f8a47a
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Showing 8 changed files with 40 additions and 13 deletions.
diff --git a/dist-c/microvium.c b/dist-c/microvium.c
@@ -731,7 +731,7 @@ typedef MVM_LONG_PTR_TYPE LongPtr;
 // Offset of field in a struct
 #define OFFSETOF(TYPE, ELEMENT) ((uint16_t)(uintptr_t)&(((TYPE *)0)->ELEMENT))
 
-// Allocation
+// Maximum size of an allocation (4kB)
 #define MAX_ALLOCATION_SIZE 0xFFF
 
 // This is the only valid way of representing NaN
@@ -4048,7 +4048,7 @@ static void* gc_allocateWithHeader(VM* vm, uint16_t sizeBytes, TeTypeCode typeCo
   uint16_t* p;
   uint16_t* end;
 
-  if (sizeBytes > 0xFFF - 3) {
+  if (sizeBytes >= (MAX_ALLOCATION_SIZE + 1)) {
     CODE_COVERAGE_ERROR_PATH(353); // Not hit
     MVM_FATAL_ERROR(vm, MVM_E_ALLOCATION_TOO_LARGE);
   } else {
@@ -7479,7 +7479,7 @@ static mvm_TeError vm_uint8ArrayNew(VM* vm, Value* slot) {
 
 mvm_Value mvm_uint8ArrayFromBytes(mvm_VM* vm, const uint8_t* data, size_t sizeBytes) {
   CODE_COVERAGE(346); // Hit
-  if (sizeBytes > 0xFFF - 3) {
+  if (sizeBytes >= (MAX_ALLOCATION_SIZE + 1)) {
     MVM_FATAL_ERROR(vm, MVM_E_ALLOCATION_TOO_LARGE);
     return VM_VALUE_UNDEFINED;
   }

diff --git a/doc/supported-builtins.md b/doc/supported-builtins.md
@@ -0,0 +1,27 @@
+# Supported Builtins
+
+### Standard builtin functions and objects
+
+`Reflect.ownKeys` - returns an array of keys for an object (only supported on non-array, non-function objects)
+
+## Additional builtin function and objects
+
+### vmExport(id, func)
+
+Export a function to be accessible to the host at the given ID.
+
+The ID can be any integer in the range 0 to 65535.
+
+(This function is only available at compile-time)
+
+### vmImport(id)
+
+Import a host function to be accessed by JS code in the VM.
+
+The ID can be any integer in the range 0 to 65535.
+
+(This function is only available at compile-time)
+
+### Microvium.newUint8Array(size)
+
+Create a Uint8Array buffer with the given size. Sizes up to 4095 bytes are supported.
diff --git a/doc/supported-language.md b/doc/supported-language.md
@@ -17,6 +17,7 @@ Note: the most up-to-date authority on supported features is the [set of test sc
  - Modules, with `import` and `export` statements
  - `throw` (but not `try`/`catch`)
  - `Reflect.ownKeys`
+ - See also [supported builtins](./supported-builtins.md)
 
 ## NOT Supported
 

diff --git a/lib/virtual-machine.ts b/lib/virtual-machine.ts
@@ -2111,7 +2111,6 @@ export class VirtualMachine {
     which can't be generated syntactically. */
     const obj_Microvium = this.newObject()
     this.globalSet('Microvium', obj_Microvium)
-    // WIP: I need documentation for these builtins
     this.setProperty(obj_Microvium, this.stringValue('newUint8Array'), this.importCustomILFunction('Microvium.newUint8Array', {
       entryBlockID: 'entry',
       blocks: {

diff --git a/native-vm/microvium.c b/native-vm/microvium.c
@@ -2642,7 +2642,7 @@ static void* gc_allocateWithHeader(VM* vm, uint16_t sizeBytes, TeTypeCode typeCo
   uint16_t* p;
   uint16_t* end;
 
-  if (sizeBytes > 0xFFF - 3) {
+  if (sizeBytes >= (MAX_ALLOCATION_SIZE + 1)) {
     CODE_COVERAGE_ERROR_PATH(353); // Not hit
     MVM_FATAL_ERROR(vm, MVM_E_ALLOCATION_TOO_LARGE);
   } else {
@@ -6073,7 +6073,7 @@ static mvm_TeError vm_uint8ArrayNew(VM* vm, Value* slot) {
 
 mvm_Value mvm_uint8ArrayFromBytes(mvm_VM* vm, const uint8_t* data, size_t sizeBytes) {
   CODE_COVERAGE(346); // Hit
-  if (sizeBytes > 0xFFF - 3) {
+  if (sizeBytes >= (MAX_ALLOCATION_SIZE + 1)) {
     MVM_FATAL_ERROR(vm, MVM_E_ALLOCATION_TOO_LARGE);
     return VM_VALUE_UNDEFINED;
   }

diff --git a/native-vm/microvium_internals.h b/native-vm/microvium_internals.h
@@ -201,7 +201,7 @@ typedef MVM_LONG_PTR_TYPE LongPtr;
 // Offset of field in a struct
 #define OFFSETOF(TYPE, ELEMENT) ((uint16_t)(uintptr_t)&(((TYPE *)0)->ELEMENT))
 
-// Allocation
+// Maximum size of an allocation (4kB)
 #define MAX_ALLOCATION_SIZE 0xFFF
 
 // This is the only valid way of representing NaN

diff --git a/size-test/output/size.txt b/size-test/output/size.txt
@@ -1,2 +1,2 @@
    text	   data	    bss	    dec	    hex	filename
-   9260	      0	      0	   9260	   242c	output/microvium.o
+   9256	      0	      0	   9256	   2428	output/microvium.o
diff --git a/test/getting-started/code/microvium/microvium.c b/test/getting-started/code/microvium/microvium.c
@@ -731,7 +731,7 @@ typedef MVM_LONG_PTR_TYPE LongPtr;
 // Offset of field in a struct
 #define OFFSETOF(TYPE, ELEMENT) ((uint16_t)(uintptr_t)&(((TYPE *)0)->ELEMENT))
 
-// Allocation
+// Maximum size of an allocation (4kB)
 #define MAX_ALLOCATION_SIZE 0xFFF
 
 // This is the only valid way of representing NaN
@@ -4048,7 +4048,7 @@ static void* gc_allocateWithHeader(VM* vm, uint16_t sizeBytes, TeTypeCode typeCo
   uint16_t* p;
   uint16_t* end;
 
-  if (sizeBytes > 0xFFF - 3) {
+  if (sizeBytes >= (MAX_ALLOCATION_SIZE + 1)) {
     CODE_COVERAGE_ERROR_PATH(353); // Not hit
     MVM_FATAL_ERROR(vm, MVM_E_ALLOCATION_TOO_LARGE);
   } else {
@@ -7478,8 +7478,8 @@ static mvm_TeError vm_uint8ArrayNew(VM* vm, Value* slot) {
 }
 
 mvm_Value mvm_uint8ArrayFromBytes(mvm_VM* vm, const uint8_t* data, size_t sizeBytes) {
-  CODE_COVERAGE_UNTESTED(346); // Not hit
-  if (sizeBytes > 0xFFF - 3) {
+  CODE_COVERAGE(346); // Hit
+  if (sizeBytes >= (MAX_ALLOCATION_SIZE + 1)) {
     MVM_FATAL_ERROR(vm, MVM_E_ALLOCATION_TOO_LARGE);
     return VM_VALUE_UNDEFINED;
   }
@@ -7491,7 +7491,7 @@ mvm_Value mvm_uint8ArrayFromBytes(mvm_VM* vm, const uint8_t* data, size_t sizeBy
 }
 
 mvm_TeError mvm_uint8ArrayToBytes(mvm_VM* vm, mvm_Value uint8ArrayValue, uint8_t** out_data, size_t* out_size) {
-  CODE_COVERAGE_UNTESTED(348); // Not hit
+  CODE_COVERAGE(348); // Hit
 
   // Note: while it makes sense to allow Uint8Arrays in general to live in ROM,
   // I think we can require that those that hit the FFI boundary are never