diff --git a/libc/arch-arm/bionic/setjmp.S b/libc/arch-arm/bionic/setjmp.S
index c10bd3e..30e7e23 100644
--- a/libc/arch-arm/bionic/setjmp.S
+++ b/libc/arch-arm/bionic/setjmp.S
@@ -56,12 +56,14 @@
 //
 // word   name            description
 // 0      sigflag/cookie  setjmp cookie in top 31 bits, signal mask flag in low bit
-// 1      sigmask         signal mask (not used with _setjmp / _longjmp)
-// 2      float_base      base of float registers (d8 to d15)
-// 18     float_state     floating-point status and control register
-// 19     core_base       base of core registers (r4-r11, r13-r14)
-// 29     checksum        checksum of all of the core registers, to give better error messages.
-// 30     reserved        reserved entries (room to grow)
+// 1      sigmask         64-bit signal mask (not used with _setjmp / _longjmp)
+// 2      "               "
+// 3      reserved        (unused to allow float_base to be maximally aligned)
+// 4      float_base      base of float registers (d8 to d15)
+// 20     float_state     floating-point status and control register
+// 21     core_base       base of core registers (r4-r11, r13-r14)
+// 31     checksum        checksum of all of the core registers, to give better error messages.
+// 32     reserved        reserved entries (room to grow)
 // 64
 //
 // NOTE: float_base must be at an even word index, since the
@@ -69,8 +71,8 @@
 //       that expect 8-byte alignment.
 
 #define _JB_SIGFLAG     0
-#define _JB_SIGMASK     (_JB_SIGFLAG+1)
-#define _JB_FLOAT_BASE  (_JB_SIGMASK+1)
+#define _JB_SIGMASK     (_JB_SIGFLAG + 1)
+#define _JB_FLOAT_BASE  (_JB_SIGMASK + 3)
 #define _JB_FLOAT_STATE (_JB_FLOAT_BASE + (15-8+1)*2)
 #define _JB_CORE_BASE   (_JB_FLOAT_STATE+1)
 #define _JB_CHECKSUM    (_JB_CORE_BASE+10)
@@ -151,7 +153,7 @@
   add r2, r0, #(_JB_SIGMASK * 4)
   mov r0, #2 // SIG_SETMASK
   mov r1, #0
-  bl sigprocmask
+  bl sigprocmask64
 
   // Unalign the stack.
   add sp, #4
@@ -221,7 +223,7 @@
   mov r2, #0
   add r1, r0, #(_JB_SIGMASK * 4)
   mov r0, #2 // SIG_SETMASK
-  bl sigprocmask
+  bl sigprocmask64
 
 1:
   ldmfd sp!, {r0, r1, lr}
diff --git a/libc/arch-x86/bionic/setjmp.S b/libc/arch-x86/bionic/setjmp.S
index f9f7cd7..1e1ce58 100644
--- a/libc/arch-x86/bionic/setjmp.S
+++ b/libc/arch-x86/bionic/setjmp.S
@@ -42,10 +42,10 @@
 // 3      ebp
 // 4      esi
 // 5      edi
-// 6      sigmask         signal mask (not used with _setjmp / _longjmp)
-// 7      sigflag/cookie  setjmp cookie in top 31 bits, signal mask flag in low bit
-// 8      checksum        checksum of the core registers, to give better error messages.
-// 9      reserved
+// 6      sigmask         64-bit signal mask (not used with _setjmp / _longjmp)
+// 7      "               "
+// 8      sigflag/cookie  setjmp cookie in top 31 bits, signal mask flag in low bit
+// 9      checksum        checksum of the core registers, to give better error messages.
 
 #define _JB_EDX 0
 #define _JB_EBX 1
@@ -54,8 +54,8 @@
 #define _JB_ESI 4
 #define _JB_EDI 5
 #define _JB_SIGMASK 6
-#define _JB_SIGFLAG 7
-#define _JB_CHECKSUM 8
+#define _JB_SIGFLAG 8
+#define _JB_CHECKSUM 9
 
 .macro m_mangle_registers reg
   xorl \reg,%edx
@@ -117,7 +117,7 @@
   pushl %eax
   pushl $0 // NULL
   pushl $2 // SIG_SETMASK
-  call PIC_PLT(sigprocmask)
+  call PIC_PLT(sigprocmask64)
   addl $12,%esp
   PIC_EPILOGUE
   popl %ecx
@@ -165,7 +165,7 @@
   pushl $0 // NULL
   pushl %eax
   pushl $2 // SIG_SETMASK
-  call PIC_PLT(sigprocmask)
+  call PIC_PLT(sigprocmask64)
   addl $12,%esp
   PIC_EPILOGUE