diff --git a/_run_all_tests.jai b/_run_all_tests.jai
index 10dbeb4..3d1179b 100644
--- a/_run_all_tests.jai
+++ b/_run_all_tests.jai
@@ -5,15 +5,16 @@
    // @note(judah): we use relative imports here because that'll
    // print cleaner file locations.
 
-   #import,file "./array/module.jai"(true);
-   #import,file "./encoding/module.jai"(true);
-   #import,file "./hash/module.jai"(true);
-   #import,file "./memory/module.jai"(true);
-   #import,file "./meta/module.jai"(true);
+   #import,file "./array/module.jai"(RUN_TESTS = true);
+   #import,file "./encoding/module.jai"(RUN_TESTS = true);
+   #import,file "./hash/module.jai"(RUN_TESTS = true);
+   #import,file "./memory/module.jai"(RUN_TESTS = true);
+   #import,file "./meta/module.jai"(RUN_TESTS = true);
+   #import,file "./platform/module.jai"(RUN_TESTS = true);
 
-   rmath :: #import,file "./math/module.jai"(.radians, true);
-   dmath :: #import,file "./math/module.jai"(.degrees, true);
-   tmath :: #import,file "./math/module.jai"(.turns, true);
+   rmath :: #import,file "./math/module.jai"(.radians, RUN_TESTS = true);
+   dmath :: #import,file "./math/module.jai"(.degrees, RUN_TESTS = true);
+   tmath :: #import,file "./math/module.jai"(.turns, RUN_TESTS = true);
 }
 
 
diff --git a/platform/arch.jai b/platform/arch.jai
new file mode 100644
index 0000000..35ea510
--- /dev/null
+++ b/platform/arch.jai
@@ -0,0 +1,105 @@
+// All of the architecture-specific extensions we care to look for.
+// Note: Checking for impossible extensions will always turn into a no-op (ex. NEON support on x64).
+ISA_Extension :: enum {
+   // x64
+   sse2;
+   sse3;
+   sse41;
+   sse42;
+   ssse3;
+
+   avx;
+   avx2;
+   avx512cd;
+   avx512f;
+   avx512vnni;
+
+   // arm64
+   neon;
+
+   // riscv
+   rv64ip;
+}
+
+// Returns true if the extension is supported by the current architecture.
+arch_supports :: inline ($ext: ISA_Extension) -> bool {
+   lazy_init_cpu_info();
+   return arch_has_extension(ext);
+}
+
+// Returns true if any of the extensions are supported by the current architecture.
+arch_supports_any :: inline ($extensions: ..ISA_Extension) -> bool {
+   lazy_init_cpu_info();
+
+   res: bool;
+   #insert -> string {
+      b: basic.String_Builder;
+      for extensions {
+         basic.print_to_builder(*b, "res ||= arch_has_extension(.%);\n", it);
+      }
+      return basic.builder_to_string(*b);
+   }
+   return res;
+}
+
+// Returns true if all of the extensions are supported by the current architecture.
+arch_supports_all :: inline ($extensions: ..ISA_Extension) -> bool {
+   lazy_init_cpu_info();
+
+   res: bool;
+   #insert -> string {
+      b: basic.String_Builder;
+      for extensions {
+         basic.print_to_builder(*b, "res &&= arch_has_extension(.%);\n", it);
+      }
+      return basic.builder_to_string(*b);
+   }
+   return res;
+}
+
+
+#scope_file;
+
+// @note(judah): this assumes lazy_init_cpu_info was already called
+arch_has_extension :: inline ($ext: ISA_Extension) -> bool {
+   #if CPU == {
+      case .X64; #if ext == {
+         case .sse2;       return x64.check_feature(info.feature_leaves, .SSE2);
+         case .sse3;       return x64.check_feature(info.feature_leaves, .SSE3);
+         case .sse41;      return x64.check_feature(info.feature_leaves, .SSE4_1);
+         case .sse42;      return x64.check_feature(info.feature_leaves, .SSE4_2);
+         case .ssse3;      return x64.check_feature(info.feature_leaves, .SSSE3);
+         case .avx;        return x64.check_feature(info.feature_leaves, .AVX);
+         case .avx2;       return x64.check_feature(info.feature_leaves, .AVX2);
+         case .avx512cd;   return x64.check_feature(info.feature_leaves, .AVX512CD);
+         case .avx512f;    return x64.check_feature(info.feature_leaves, .AVX512F);
+         case .avx512vnni; return x64.check_feature(info.feature_leaves, .AVX512_VNNI);
+      }
+      case .ARM64; #if ext == {
+         case .neon;
+            return true; // @note(judah): it's safe to assume neon support if we're on arm (for now)
+      }
+   }
+
+   return false;
+}
+
+info_initialized := false;
+
+lazy_init_cpu_info :: () #expand {
+   if info_initialized return;
+   info_initialized = true;
+
+   #if CPU == .X64 {
+      info = x64.get_cpu_info();
+   }
+}
+
+#if CPU == {
+   case .X64;
+      info: x64.Cpu_X86;
+      x64 :: #import "Machine_X64"; // @future
+}
+
+
+basic :: #import "Basic"; // @future
diff --git a/platform/module.jai b/platform/module.jai
new file mode 100644
index 0000000..a390cb0
--- /dev/null
+++ b/platform/module.jai
@@ -0,0 +1,7 @@
+#module_parameters(RUN_TESTS := false);
+
+#load "arch.jai";
+
+#if RUN_TESTS {
+   test :: #import "jc/test";
+}