From 59a07e28c5ef018d0c5cecd12d52ff10f5dc5b1a Mon Sep 17 00:00:00 2001
From: Test_User <hax@andrewyu.org>
Date: Fri, 19 Jul 2024 23:26:45 -0400
Subject: Minimal support for non-semaphore-supporting systems

---
 Makefile | 16 ++++++++++++++++
 mutex.h  | 22 +++++++++++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 9a32b59..fe1f263 100644
--- a/Makefile
+++ b/Makefile
@@ -51,6 +51,7 @@ LDFLAGS = -lpthread
 	printf '%s\n' 'LAST_SERVICES_PSEUDOCLIENT = $(SERVICES_PSEUDOCLIENT)' >> .makeopts
 	printf '%s\n' 'LAST_SAFE_STACK = $(SAFE_STACK)' >> .makeopts
 	printf '%s\n' 'LAST_FUTEX = $(FUTEX)' >> .makeopts
+	printf '%s\n' 'LAST_MISERABLE_SPINLOCKS = $(MISERABLE_SPINLOCKS)' >> .makeopts
 	printf '%s\n' 'LAST_ATOMICS = $(ATOMICS)' >> .makeopts
 	printf '%s\n' 'LAST_CFLAGS = $(ORIGINAL_CFLAGS)' >> .makeopts
 	printf '%s\n' 'LAST_CC = $(CC)' >> .makeopts
@@ -223,6 +224,14 @@ else
 FUTEX := $(LAST_FUTEX)
 endif
 
+ifneq ($(MISERABLE_SPINLOCKS),)
+ifneq ($(MISERABLE_SPINLOCKS),$(LAST_MISERABLE_SPINLOCKS))
+rebuild = 1
+endif
+else
+MISERABLE_SPINLOCKS := $(LAST_MISERABLE_SPINLOCKS)
+endif
+
 ifneq ($(ATOMICS),)
 ifneq ($(ATOMICS),$(LAST_ATOMICS))
 rebuild = 1
@@ -415,6 +424,13 @@ ifeq ($(FUTEX),1)
 CFLAGS += -DUSE_FUTEX
 endif
 
+ifeq ($(MISERABLE_SPINLOCKS),1)
+ifeq ($(FUTEX),1)
+$(error Miserable spinlocks are only enabled when noy using futexes)
+endif
+CFLAGS += -DUSE_MISERABLE_SPINLOCKS
+endif
+
 ifeq ($(ATOMICS),1)
 CFLAGS += -DUSE_ATOMICS
 endif
diff --git a/mutex.h b/mutex.h
index a341152..7d1b4b2 100644
--- a/mutex.h
+++ b/mutex.h
@@ -26,7 +26,7 @@
 
 #pragma once
 
-#ifdef USE_FUTEX
+#if defined(USE_FUTEX)
 
 #include <unistd.h>
 #include <sys/syscall.h>
@@ -61,6 +61,26 @@ inline void mutex_destroy(uint32_t *futex) {
 	return;
 }
 
+#elif defined(USE_MISERABLE_SPINLOCKS)
+
+#define MUTEX_TYPE char
+
+inline void mutex_init(char *lock) {
+	*lock = 0;
+}
+
+inline void mutex_lock(char *lock) {
+	while (__sync_lock_test_and_set(lock, 0x1));
+}
+
+inline void mutex_unlock(char *lock) {
+	__sync_lock_release(lock);
+}
+
+inline void mutex_destroy(char *lock) {
+	return;
+}
+
 #else
 
 #include <semaphore.h>
-- 
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