diff --git a/src/asm/make_i386_sysv_elf_gas.S b/src/asm/make_i386_sysv_elf_gas.S
index 0b7ab811..d945c0b2 100644
--- a/src/asm/make_i386_sysv_elf_gas.S
+++ b/src/asm/make_i386_sysv_elf_gas.S
@@ -40,8 +40,8 @@ make_fcontext:
     /* shift address in EAX to lower 16 byte boundary */
     andl  $-16, %eax
 
-    /* reserve space for context-data on context-stack */
-    leal  -0x2c(%eax), %eax
+    /* reserve space for context-data on context-stack, and align the stack */
+    leal  -0x30(%eax), %eax
 
     /* third arg of make_fcontext() == address of context-function */
     /* stored in EBX */
diff --git a/src/asm/make_i386_sysv_macho_gas.S b/src/asm/make_i386_sysv_macho_gas.S
index fdcdb7c8..98e23a6e 100644
--- a/src/asm/make_i386_sysv_macho_gas.S
+++ b/src/asm/make_i386_sysv_macho_gas.S
@@ -38,8 +38,8 @@ _make_fcontext:
     /* shift address in EAX to lower 16 byte boundary */
     andl  $-16, %eax
 
-    /* reserve space for context-data on context-stack */
-    leal  -0x2c(%eax), %eax
+    /* reserve space for context-data on context-stack, and align the stack */
+    leal  -0x30(%eax), %eax
 
     /* third arg of make_fcontext() == address of context-function */
     /* stored in EBX */