diff --git a/arch/sim/src/sim/up_initialstate.c b/arch/sim/src/sim/up_initialstate.c
index 3ddb1128d7..129d3be8ee 100644
--- a/arch/sim/src/sim/up_initialstate.c
+++ b/arch/sim/src/sim/up_initialstate.c
@@ -67,6 +67,6 @@
 void up_initial_state(struct tcb_s *tcb)
 {
   memset(&tcb->xcp, 0, sizeof(struct xcptcontext));
-  tcb->xcp.regs[JB_SP] = (xcpt_reg_t)tcb->adj_stack_ptr;
+  tcb->xcp.regs[JB_SP] = (xcpt_reg_t)tcb->adj_stack_ptr - sizeof(xcpt_reg_t);
   tcb->xcp.regs[JB_PC] = (xcpt_reg_t)tcb->start;
 }
diff --git a/arch/sim/src/sim/up_stackframe.c b/arch/sim/src/sim/up_stackframe.c
index eecb3668af..887de5c703 100644
--- a/arch/sim/src/sim/up_stackframe.c
+++ b/arch/sim/src/sim/up_stackframe.c
@@ -124,7 +124,7 @@ FAR void *up_stack_frame(FAR struct tcb_s *tcb, size_t frame_size)
 
   /* Reset the initial state */
 
-  tcb->xcp.regs[JB_SP] = (xcpt_reg_t)tcb->adj_stack_ptr;
+  tcb->xcp.regs[JB_SP] = (xcpt_reg_t)tcb->adj_stack_ptr - sizeof(xcpt_reg_t);
 
   /* And return a pointer to the allocated memory */