setjmp: do not disable interrupts (#1) (DONE)

SR.BL=1 could cause problems if setjmp or longjmp is loader over a page
boundary and the second page is not loaded when interrupts are masked.

SR.IMASK=15 is another option, but it seems unnecessary per #1.

Blocking interrupts in longjmp did not make too much sense because the
blocked SR was immediately replaced by the restored one.

STATUS

@@ -68,8 +68,8 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
 7.12 <math.h> => OpenLibm
 
 7.13 <setjmp.h>
-!    7.13.1 setjmp: TEST
-!    7.13.2 longjmp: TEST
+     7.13.1 setjmp: DONE
+     7.13.2 longjmp: DONE
 
 7.14 <signal.h>
 !    7.14.1    Macros and stuff: TODO
@@ -95,6 +95,7 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
 !    7.19.10 Error-handling functions: TODO
 
 7.20 <stdlib.h>
+     7.20      RAND_MAX, MB_CUR_MAX: TODO
      7.20.1.1  atof: DONE
      7.20.1.2  atoi, atol, atoll: DONE
      7.20.1.3  strtod, strtof, strtold: DONE

src/libc/setjmp/target/sh-generic/longjmp.S

@@ -18,15 +18,6 @@ _longjmp:
 	movt	r9
 	add	r5, r9
 
-	! block interrupt
-int_block:
-	stc	sr, r1
-	mov	#0x10, r2
-	shll8	r2
-	shll16	r2
-	or	r2, r1
-	ldc 	r1, sr
-
 context_switch:
 	! load the old SR register first to force register bank switch
 	! (if needed) then move the context and the returned value into

src/libc/setjmp/target/sh-generic/setjmp.S

@@ -5,18 +5,12 @@
 .align 2
 /*
 ** int setjmp(jmp_buf env)
-** Store the calling environment in ENV, also saving the signal mask.
+** Store the calling environment in ENV.
 ** Return 0.
 */
 _setjmp:
 	! block interrupt
-	stc	sr, r1
-	mov	r1, r3
-	mov	#0x10, r2
-	shll8	r2
-	shll16	r2
-	or	r2, r1
-	ldc 	r1, sr
+	stc	sr, r3
 
 	! save current context
 	! @note: r3 is the saved SR regsiter
@@ -35,9 +29,6 @@ _setjmp:
 	mov.l	r8, @-r4
 	mov.l	r3, @-r4
 
-	! restore sr
-	ldc	r3, sr
-
 	! return
 	rts
 	mov	#0, r0