diff --git a/.github/workflows/continuous-integration-v2.yml b/.github/workflows/continuous-integration-v2.yml
index fa4bb41..957589d 100644
--- a/.github/workflows/continuous-integration-v2.yml
+++ b/.github/workflows/continuous-integration-v2.yml
@@ -14,21 +14,24 @@ on:
       - dev
   workflow_dispatch:
 
-#testing the CI workflows while nothing is functional yet
+#CI workflows using a matrix
 jobs:
-  test-ubuntu-latest:
-    runs-on: ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v4
-      - name: make tests (ubuntu)
-        run: make tests
-  
-  test-windows-latest:
-    runs-on: windows-latest
+  run-test-suites:
+    strategy:
+      matrix:
+        platforms:
+          - { os: ubuntu-latest, preinstall: sudo apt-get install gdb, gdb_skip: false }
+          - { os: windows-latest, preinstall: , gdb_skip: false }
+          - { os: macos-latest, preinstall: , gdb_skip: true }
+        commands:
+          - make tests
+          - make tests-gdb
     
+    runs-on: ${{ matrix.platforms.os }}
     steps:
       - uses: actions/checkout@v4
-      - name: make tests (windows)
-        run: make tests
-
+      - name: Preinstall dependencies
+        run: ${{ matrix.platforms.preinstall }}
+      - name: run the test suites
+        if: matrix.platforms.gdb_skip != true
+        run: ${{ matrix.commands }}
diff --git a/makefile b/makefile
index 5afdc74..4305bf4 100644
--- a/makefile
+++ b/makefile
@@ -19,6 +19,10 @@ all: clean tests
 tests:
 	$(MAKE) -C tests -k
 
+.PHONY: tests-gdb
+tests-gdb:
+	$(MAKE) -C tests all-gdb -k
+
 #util targets
 $(TOY_OUTDIR):
 	mkdir $(TOY_OUTDIR)
diff --git a/source/toy_ast.h b/source/toy_ast.h
index 6a7fd4e..e87253f 100644
--- a/source/toy_ast.h
+++ b/source/toy_ast.h
@@ -110,14 +110,14 @@ typedef struct Toy_AstEnd {
 	Toy_AstType type;
 } Toy_AstEnd;
 
-union Toy_Ast {
-	Toy_AstType type; //4
-	Toy_AstBlock block; //12
-	Toy_AstValue value; //12
-	Toy_AstUnary unary; //12
-	Toy_AstBinary binary; //16
-	Toy_AstGroup group; //8
-	Toy_AstPass pass; //4
-	Toy_AstError error; //4
-	Toy_AstEnd end; //4
-}; //16
+union Toy_Ast {             //32 | 64 BITNESS
+	Toy_AstType type;       //4  | 4
+	Toy_AstBlock block;     //16 | 32
+	Toy_AstValue value;     //12 | 12
+	Toy_AstUnary unary;     //12 | 16
+	Toy_AstBinary binary;   //16 | 24
+	Toy_AstGroup group;     //8  | 16
+	Toy_AstPass pass;       //4  | 4
+	Toy_AstError error;     //4  | 4
+	Toy_AstEnd end;         //4  | 4
+};                          //16 | 32
diff --git a/source/toy_common.h b/source/toy_common.h
index d31dc10..642b3fd 100644
--- a/source/toy_common.h
+++ b/source/toy_common.h
@@ -6,29 +6,38 @@
 #include <stddef.h>
 
 //TOY_API is platform-dependant, and marks publicly usable API functions
-#if defined(__GNUC__)
+#if defined(__linux__)
 	#define TOY_API extern
-#elif defined(_MSC_VER)
-	#ifndef TOY_EXPORT
+#elif defined(_WIN32) || defined(_WIN64)
+	#if defined(TOY_EXPORT)
+		#define TOY_API __declspec(dllexport)
+	#elif defined(TOY_IMPORT)
 		#define TOY_API __declspec(dllimport)
 	#else
-		#define TOY_API __declspec(dllexport)
+		#define TOY_API extern
 	#endif
+#elif defined(__APPLE__)
+	#define TOY_API extern
 #else
 	//generic solution
 	#define TOY_API extern
 #endif
 
 //TOY_BITNESS is used to encourage memory-cache friendliness
-//source: https://www.linuxquestions.org/questions/programming-9/c-preprocessor-define-for-32-vs-64-bit-long-int-4175658579/
-#if defined(__GNUC__)
-	#if defined(__x86_64)
+#if defined(__linux__)
+	#if defined(__LP64__)
 		#define TOY_BITNESS 64
 	#else
 		#define TOY_BITNESS 32
 	#endif
-#elif defined(_MSC_VER)
-	#if defined(_M_X64)
+#elif defined(_WIN32) || defined(_WIN64)
+	#if defined(_WIN64)
+		#define TOY_BITNESS 64
+	#else
+		#define TOY_BITNESS 32
+	#endif
+#elif defined(__APPLE__)
+	#if defined(__LP64__)
 		#define TOY_BITNESS 64
 	#else
 		#define TOY_BITNESS 32
diff --git a/source/toy_keywords.c b/source/toy_keywords.c
index dec78a4..b105882 100644
--- a/source/toy_keywords.c
+++ b/source/toy_keywords.c
@@ -41,6 +41,7 @@ const Toy_KeywordTypeTuple Toy_private_keywords[] = {
 	{TOY_TOKEN_KEYWORD_TYPEOF, "typeof"},
 	{TOY_TOKEN_KEYWORD_VAR, "var"},
 	{TOY_TOKEN_KEYWORD_WHILE, "while"},
+	{TOY_TOKEN_KEYWORD_YIELD, "yield"},
 
 	//literal values
 	{TOY_TOKEN_LITERAL_TRUE, "true"},
diff --git a/source/toy_opcodes.h b/source/toy_opcodes.h
index 23e5767..176964d 100644
--- a/source/toy_opcodes.h
+++ b/source/toy_opcodes.h
@@ -36,5 +36,5 @@ typedef enum Toy_OpcodeType {
 	//meta instructions
 	TOY_OPCODE_PASS,
 	TOY_OPCODE_ERROR,
-	TOY_OPCODE_EOF,
+	TOY_OPCODE_EOF = 255,
 } Toy_OpcodeType;
diff --git a/source/toy_parser.c b/source/toy_parser.c
index 070f069..d4efab5 100644
--- a/source/toy_parser.c
+++ b/source/toy_parser.c
@@ -154,6 +154,7 @@ static ParsingTuple parsingRulesetTable[] = {
 	{PREC_NONE,NULL,NULL},// TOY_TOKEN_KEYWORD_TYPEOF,
 	{PREC_NONE,NULL,NULL},// TOY_TOKEN_KEYWORD_VAR,
 	{PREC_NONE,NULL,NULL},// TOY_TOKEN_KEYWORD_WHILE,
+	{PREC_NONE,NULL,NULL},// TOY_TOKEN_KEYWORD_YIELD,
 
 	//literal values
 	{PREC_PRIMARY,atomic,NULL},// TOY_TOKEN_LITERAL_TRUE,
diff --git a/source/toy_routine.c b/source/toy_routine.c
index ce5d9de..3ff9b07 100644
--- a/source/toy_routine.c
+++ b/source/toy_routine.c
@@ -281,12 +281,12 @@ static void* writeRoutine(Toy_Routine* rt, Toy_Ast* ast) {
 		expand(&buffer, &capacity, &count, rt->codeCount);
 		memcpy((buffer + count), rt->code, rt->codeCount);
 
-		((int*)buffer)[codeAddr] = count;
+		*((int*)(buffer + codeAddr)) = count;
 		count += rt->codeCount;
 	}
 
 	//finally, record the total size, and return the result
-	((int*)buffer)[0] = count;
+	*((int*)buffer) = count;
 
 	return buffer;
 }
diff --git a/source/toy_token_types.h b/source/toy_token_types.h
index f60eaba..849026f 100644
--- a/source/toy_token_types.h
+++ b/source/toy_token_types.h
@@ -43,6 +43,7 @@ typedef enum Toy_TokenType {
 	TOY_TOKEN_KEYWORD_TYPEOF,
 	TOY_TOKEN_KEYWORD_VAR,
 	TOY_TOKEN_KEYWORD_WHILE,
+	TOY_TOKEN_KEYWORD_YIELD,
 
 	//literal values
 	TOY_TOKEN_LITERAL_TRUE,
diff --git a/tests/cases/test_ast.c b/tests/cases/test_ast.c
index be56386..9e15393 100644
--- a/tests/cases/test_ast.c
+++ b/tests/cases/test_ast.c
@@ -3,6 +3,33 @@
 
 #include <stdio.h>
 
+int test_sizeof_ast_64bit() {
+#define TEST_SIZEOF(type, size) \
+	if (sizeof(type) != size) { \
+		fprintf(stderr, TOY_CC_ERROR "ERROR: sizeof(" #type ") is %d, expected %d\n" TOY_CC_RESET, (int)sizeof(type), size); \
+		++err; \
+	}
+
+	//count errors
+	int err = 0;
+
+	//run for each type
+	TEST_SIZEOF(Toy_AstType, 4);
+	TEST_SIZEOF(Toy_AstBlock, 32);
+	TEST_SIZEOF(Toy_AstValue, 12);
+	TEST_SIZEOF(Toy_AstUnary, 16);
+	TEST_SIZEOF(Toy_AstBinary, 24);
+	TEST_SIZEOF(Toy_AstGroup, 16);
+	TEST_SIZEOF(Toy_AstPass, 4);
+	TEST_SIZEOF(Toy_AstError, 4);
+	TEST_SIZEOF(Toy_AstEnd, 4);
+	TEST_SIZEOF(Toy_Ast, 32);
+
+#undef TEST_SIZEOF
+
+	return -err;
+}
+
 int test_sizeof_ast_32bit() {
 #define TEST_SIZEOF(type, size) \
 	if (sizeof(type) != size) { \
@@ -22,6 +49,7 @@ int test_sizeof_ast_32bit() {
 	TEST_SIZEOF(Toy_AstGroup, 8);
 	TEST_SIZEOF(Toy_AstPass, 4);
 	TEST_SIZEOF(Toy_AstError, 4);
+	TEST_SIZEOF(Toy_AstEnd, 4);
 	TEST_SIZEOF(Toy_Ast, 16);
 
 #undef TEST_SIZEOF
@@ -168,7 +196,15 @@ int main() {
 	//run each test set, returning the total errors given
 	int total = 0, res = 0;
 
-#if TOY_BITNESS == 32
+
+#if TOY_BITNESS == 64
+	res = test_sizeof_ast_64bit();
+	total += res;
+
+	if (res == 0) {
+		printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
+	}
+#elif TOY_BITNESS == 32
 	res = test_sizeof_ast_32bit();
 	total += res;
 
@@ -176,7 +212,7 @@ int main() {
 		printf(TOY_CC_NOTICE "All good\n" TOY_CC_RESET);
 	}
 #else
-	fprintf(stderr, TOY_CC_WARN "WARNING: Skipping test_sizeof_ast_32bit(); Can't determine the 'bitness' of this platform\n" TOY_CC_RESET);
+	fprintf(stderr, TOY_CC_WARN "WARNING: Skipping test_sizeof_ast_*bit(); Can't determine the 'bitness' of this platform (seems to be %d)\n" TOY_CC_RESET, TOY_BITNESS);
 #endif
 
 	{
diff --git a/tests/makefile b/tests/makefile
index 6a61a57..87869f1 100644
--- a/tests/makefile
+++ b/tests/makefile
@@ -3,6 +3,16 @@ CC=gcc
 CFLAGS=-g -Wall -Werror -Wno-unused-parameter -Wno-unused-function -Wno-unused-variable
 LIBS=-lm
 
+ifeq ($(shell uname),Linux)
+LDFLAG=-Wl,--gc-sections
+else ifeq ($(OS),Windows_NT)
+LDFLAG=-Wl,--gc-sections
+else ifeq ($(shell uname),Darwin)
+LDFLAG=-Wl,-dead_strip
+else
+	@echo "LDFLAG set failed - what platform is this?"
+endif
+
 #directories
 TEST_ROOTDIR=..
 TEST_SOURCEDIR=$(TEST_ROOTDIR)/$(TOY_SOURCEDIR)
@@ -16,14 +26,20 @@ TEST_SOURCEFILES=$(addprefix $(TOY_ROOTDIR)/,$(TOY_SOURCEFILES))
 TEST_CASESFILES=$(wildcard $(TEST_CASESDIR)/*.c)
 
 #build the object files, compile the test cases, and run
-all: clean build-source build-cases $(addprefix $(TEST_OUTDIR)/,$(notdir $(TEST_CASESFILES:%.c=%.exe)))
+all: clean build-source build-cases build-link build-run
 
-#targets for each set of source files
+#targets for each step
 .PHONY: build-source
 build-source: $(TEST_OUTDIR) $(TEST_OBJDIR) $(addprefix $(TEST_OBJDIR)/,$(notdir $(TEST_SOURCEFILES:.c=.o)))
 
 .PHONY: build-cases
-build-cases: $(TEST_OUTDIR) $(TEST_OBJDIR) $(addprefix $(TEST_OBJDIR)/,$(notdir $(TEST_CASESFILES:.c=.o))) 
+build-cases: $(TEST_OUTDIR) $(TEST_OBJDIR) $(addprefix $(TEST_OBJDIR)/,$(notdir $(TEST_CASESFILES:.c=.o)))
+
+.PHONY: build-link
+build-link: $(TEST_OUTDIR) $(TEST_OBJDIR) $(addprefix $(TEST_OUTDIR)/,$(notdir $(TEST_CASESFILES:%.c=%.exe)))
+
+.PHONY: build-run
+build-run: $(addprefix $(TEST_OUTDIR)/,$(notdir $(TEST_CASESFILES:%.c=%.exe))) $(addprefix $(TEST_OUTDIR)/,$(notdir $(TEST_CASESFILES:%.c=%.run)))
 
 #util targets
 $(TEST_OUTDIR):
@@ -32,17 +48,29 @@ $(TEST_OUTDIR):
 $(TEST_OBJDIR):
 	mkdir $(TEST_OBJDIR)
 
-#compilation step
+#compilation steps
 $(TEST_OBJDIR)/%.o: $(TEST_SOURCEDIR)/%.c
 	$(CC) -c -o $@ $< $(addprefix -I,$(TEST_SOURCEDIR)) $(CFLAGS) -fdata-sections -ffunction-sections
 
 $(TEST_OBJDIR)/%.o: $(TEST_CASESDIR)/%.c
 	$(CC) -c -o $@ $< $(addprefix -I,$(TEST_SOURCEDIR) $(TEST_CASESDIR)) $(CFLAGS) -fdata-sections -ffunction-sections
 
-#final linking step (with extra flags to strip dead code)
 $(TEST_OUTDIR)/%.exe: $(TEST_OBJDIR)/%.o
-	@$(CC) -o $@ $< $(addprefix $(TEST_OBJDIR)/,$(notdir $(TEST_SOURCEFILES:.c=.o))) $(CFLAGS) $(LIBS) -Wl,--gc-sections
-	$@
+	@$(CC) -o $@ $< $(addprefix $(TEST_OBJDIR)/,$(notdir $(TEST_SOURCEFILES:.c=.o))) $(CFLAGS) $(LIBS) $(LDFLAGS)
+
+.PRECIOUS: $(TEST_OUTDIR)/%.run
+$(TEST_OUTDIR)/%.run: $(TEST_OUTDIR)/%.exe
+	$<
+
+#debugging targets
+all-gdb: clean build-source build-cases build-link build-run-gdb
+
+.PHONY: build-run-gdb
+build-run-gdb: $(addprefix $(TEST_OUTDIR)/,$(notdir $(TEST_CASESFILES:%.c=%.exe))) $(addprefix $(TEST_OUTDIR)/,$(notdir $(TEST_CASESFILES:%.c=%.run-gdb)))
+
+.PRECIOUS: $(TEST_OUTDIR)/%.run-gdb
+$(TEST_OUTDIR)/%.run-gdb: $(TEST_OUTDIR)/%.exe
+	gdb $< -ex "run" --batch
 
 #util commands
 .PHONY: clean