diff --git a/include/mimalloc/atomic.h b/include/mimalloc/atomic.h
index 42e76e7b..857e9f02 100644
--- a/include/mimalloc/atomic.h
+++ b/include/mimalloc/atomic.h
@@ -281,7 +281,7 @@ typedef _Atomic(uintptr_t) mi_atomic_once_t;
 static inline bool mi_atomic_once( mi_atomic_once_t* once ) {
   if (mi_atomic_load_relaxed(once) != 0) return false;     // quick test 
   uintptr_t expected = 0;
-  return mi_atomic_cas_strong_acq_rel(once, &expected, 1UL); // try to set to 1
+  return mi_atomic_cas_strong_acq_rel(once, &expected, (uintptr_t)1); // try to set to 1
 }
 
 typedef _Atomic(uintptr_t) mi_atomic_guard_t;
@@ -314,7 +314,7 @@ static inline void mi_atomic_yield(void) {
 }
 #elif (defined(__GNUC__) || defined(__clang__)) && \
       (defined(__x86_64__) || defined(__i386__) || defined(__arm__) || defined(__armel__) || defined(__ARMEL__) || \
-       defined(__aarch64__) || defined(__powerpc__) || defined(__ppc__) || defined(__PPC__))
+       defined(__aarch64__) || defined(__powerpc__) || defined(__ppc__) || defined(__PPC__)) || defined(__POWERPC__)
 #if defined(__x86_64__) || defined(__i386__)
 static inline void mi_atomic_yield(void) {
   __asm__ volatile ("pause" ::: "memory");
@@ -327,10 +327,16 @@ static inline void mi_atomic_yield(void) {
 static inline void mi_atomic_yield(void) {
   __asm__ volatile("yield" ::: "memory");
 }
-#elif defined(__powerpc__) || defined(__ppc__) || defined(__PPC__)
+#elif defined(__powerpc__) || defined(__ppc__) || defined(__PPC__) || defined(__POWERPC__)
+#ifdef __APPLE__
+static inline void mi_atomic_yield(void) {
+  __asm__ volatile ("or r27,r27,r27" ::: "memory");
+}
+#else
 static inline void mi_atomic_yield(void) {
   __asm__ __volatile__ ("or 27,27,27" ::: "memory");
 }
+#endif
 #elif defined(__armel__) || defined(__ARMEL__)
 static inline void mi_atomic_yield(void) {
   __asm__ volatile ("nop" ::: "memory");
diff --git a/include/mimalloc/types.h b/include/mimalloc/types.h
index 2a5d172d..85d7e813 100644
--- a/include/mimalloc/types.h
+++ b/include/mimalloc/types.h
@@ -165,7 +165,7 @@ typedef int32_t  mi_ssize_t;
 // Derived constants
 #define MI_SEGMENT_SIZE                   (MI_ZU(1)<<MI_SEGMENT_SHIFT)
 #define MI_SEGMENT_ALIGN                  (MI_SEGMENT_SIZE)
-#define MI_SEGMENT_MASK                   (MI_SEGMENT_ALIGN - 1)
+#define MI_SEGMENT_MASK                   ((uintptr_t)(MI_SEGMENT_ALIGN - 1))
 
 #define MI_SMALL_PAGE_SIZE                (MI_ZU(1)<<MI_SMALL_PAGE_SHIFT)
 #define MI_MEDIUM_PAGE_SIZE               (MI_ZU(1)<<MI_MEDIUM_PAGE_SHIFT)
diff --git a/src/prim/osx/alloc-override-zone.c b/src/prim/osx/alloc-override-zone.c
index 80bcfa93..0e0a99d9 100644
--- a/src/prim/osx/alloc-override-zone.c
+++ b/src/prim/osx/alloc-override-zone.c
@@ -195,7 +195,7 @@ static malloc_introspection_t mi_introspect = {
   .log = &intro_log,
   .force_lock = &intro_force_lock,
   .force_unlock = &intro_force_unlock,
-#if defined(MAC_OS_X_VERSION_10_6) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6)
+#if defined(MAC_OS_X_VERSION_10_6) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6) && !defined(__ppc__)
   .statistics = &intro_statistics,
   .zone_locked = &intro_zone_locked,
 #endif
@@ -216,7 +216,7 @@ static malloc_zone_t mi_malloc_zone = {
   .batch_malloc = &zone_batch_malloc,
   .batch_free = &zone_batch_free,
   .introspect = &mi_introspect,
-#if defined(MAC_OS_X_VERSION_10_6) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6)
+#if defined(MAC_OS_X_VERSION_10_6) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6) && !defined(__ppc__)
   #if defined(MAC_OS_X_VERSION_10_14) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14)
   .version = 10,
   #else
diff --git a/src/prim/unix/prim.c b/src/prim/unix/prim.c
index b662698c..de50f594 100644
--- a/src/prim/unix/prim.c
+++ b/src/prim/unix/prim.c
@@ -605,11 +605,19 @@ void _mi_prim_process_info(mi_process_info_t* pinfo)
   pinfo->page_faults = 0;
 #elif defined(__APPLE__)
   pinfo->peak_rss = rusage.ru_maxrss;         // macos reports in bytes
+  #ifdef MACH_TASK_BASIC_INFO
   struct mach_task_basic_info info;
   mach_msg_type_number_t infoCount = MACH_TASK_BASIC_INFO_COUNT;
   if (task_info(mach_task_self(), MACH_TASK_BASIC_INFO, (task_info_t)&info, &infoCount) == KERN_SUCCESS) {
     pinfo->current_rss = (size_t)info.resident_size;
   }
+  #else
+  struct task_basic_info info;
+  mach_msg_type_number_t infoCount = TASK_BASIC_INFO_COUNT;
+  if (task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)&info, &infoCount) == KERN_SUCCESS) {
+    pinfo->current_rss = (size_t)info.resident_size;
+  }
+  #endif
 #else
   pinfo->peak_rss = rusage.ru_maxrss * 1024;  // Linux/BSD report in KiB
 #endif