diff --git a/arch/sim/include/setjmp.h b/arch/sim/include/setjmp.h
index 7e510ef005..879e31c0f2 100644
--- a/arch/sim/include/setjmp.h
+++ b/arch/sim/include/setjmp.h
@@ -49,7 +49,7 @@
 #    define JB_R13            (4*8)
 #    define JB_R14            (5*8)
 #    define JB_R15            (6*8)
-#    define JB_RSI            (7*8)
+#    define JB_RIP            (7*8)
 #    define JB_FLAG           (8*8)
 
 #  else
@@ -61,7 +61,7 @@
 #    define JB_R13            (4)
 #    define JB_R14            (5)
 #    define JB_R15            (6)
-#    define JB_RSI            (7)
+#    define JB_RIP            (7)
 #    define JB_FLAG           (8)
 
 #  endif /* __ASSEMBLY__ */
@@ -70,7 +70,7 @@
 
 #  define JB_FP               JB_RBP
 #  define JB_SP               JB_RSP
-#  define JB_PC               JB_RSI
+#  define JB_PC               JB_RIP
 
 #elif defined(CONFIG_HOST_X86) || defined(CONFIG_SIM_M32)
   /* Storage order: %ebx, %esi, %edi, %ebp, sp, and return PC */
@@ -84,8 +84,8 @@
 #    define JB_ESI            (1*4)
 #    define JB_EDI            (2*4)
 #    define JB_EBP            (3*4)
-#    define JB_SP             (4*4)
-#    define JB_PC             (5*4)
+#    define JB_ESP            (4*4)
+#    define JB_EIP            (5*4)
 #    define JB_FLAG           (6*4)
 #    define JB_FLAG1          (7*4)
 
@@ -95,8 +95,8 @@
 #    define JB_ESI            (1)
 #    define JB_EDI            (2)
 #    define JB_EBP            (3)
-#    define JB_SP             (4)
-#    define JB_PC             (5)
+#    define JB_ESP            (4)
+#    define JB_EIP            (5)
 #    define JB_FLAG           (6)
 #    define JB_FLAG1          (7)
 
@@ -105,6 +105,8 @@
 /* Compatibility definitions */
 
 #  define JB_FP               JB_EBP
+#  define JB_SP               JB_ESP
+#  define JB_PC               JB_EIP
 
 #elif defined(CONFIG_HOST_ARM)
 
diff --git a/fs/procfs/fs_procfstcbinfo.c b/fs/procfs/fs_procfstcbinfo.c
index ce65726e60..083fde59f0 100644
--- a/fs/procfs/fs_procfstcbinfo.c
+++ b/fs/procfs/fs_procfstcbinfo.c
@@ -195,7 +195,7 @@ static ssize_t tcbinfo_read(FAR struct file *filep, FAR char *buffer,
   if (filep->f_pos == 0)
     {
       linesize = procfs_snprintf(attr->line, TCBINFO_LINELEN,
-                                 "pointer %p size %d\n", &g_tcbinfo,
+                                 "pointer %p size %zu\n", &g_tcbinfo,
                                   sizeof(struct tcbinfo_s));
 
       /* Save the linesize in case we are re-entered with f_pos > 0 */
diff --git a/include/nuttx/sched.h b/include/nuttx/sched.h
index a0815966ac..e56ca2bcc2 100644
--- a/include/nuttx/sched.h
+++ b/include/nuttx/sched.h
@@ -183,7 +183,9 @@
 #  define TCB_NAME_OFF               0
 #endif
 #  define TCB_REGS_OFF               offsetof(struct tcb_s, xcp.regs)
-#  define TCB_REG_OFF(reg)           (reg * sizeof(uint32_t))
+#  define TCB_REG_OFF(reg)           (reg * sizeof(uintptr_t))
+#  define TCB_STACK_OFF              offsetof(struct tcb_s, stack_base_ptr)
+#  define TCB_STACK_SIZE_OFF         offsetof(struct tcb_s, adj_stack_size)
 #endif
 
 /* Get a pointer to the process' memory map struct from the task_group */
diff --git a/libs/libc/machine/sim/arch_setjmp_x86_64.S b/libs/libc/machine/sim/arch_setjmp_x86_64.S
index 0dccb23980..cc747f8f8a 100644
--- a/libs/libc/machine/sim/arch_setjmp_x86_64.S
+++ b/libs/libc/machine/sim/arch_setjmp_x86_64.S
@@ -110,7 +110,7 @@ SYMBOL(setjmp):
 	movq	%r13, JB_R13(REGS)	/* Save 5: r13 */
 	movq	%r14, JB_R14(REGS)	/* Save 6: r14 */
 	movq	%r15, JB_R15(REGS)	/* Save 7: r15 */
-	movq	%rsi, JB_RSI(REGS)	/* Save 8: Return address */
+	movq	%rsi, JB_RIP(REGS)	/* Save 8: Return address */
 
 	ret
 
@@ -139,9 +139,9 @@ SYMBOL(longjmp):
 	movq	JB_R14(REGS),%r14	/* Load 6: r14 */
 	movq	JB_R15(REGS),%r15	/* Load 7: rbp */
 
-	/* Jump to the saved return address (rsi)  */
+	/* Jump to the saved return address (rip)  */
 
-	jmp		*JB_RSI(REGS)
+	jmp		*JB_RIP(REGS)
 
 #ifdef __ELF__
 	.size SYMBOL(longjmp), . - SYMBOL(longjmp)