Recode to clean up function prologues and epilogue and to allow the functions

 to be used in a Thumb based toolchain.

2 files changed, 105 insertions, 65 deletions

diff --git a/newlib/ChangeLog b/newlib/ChangeLog
index caee23f88..3b71567c0 100644
--- a/newlib/ChangeLog
+++ b/newlib/ChangeLog
@@ -1,3 +1,9 @@
+2000-08-09  Nick Clifton  <nickc@cygnus.com>
+
+	* libc/sys/arm/setjmp.S: Recode to clean up function prologues and
+	epilogue and to allow the functions to be used in a Thumb based
+	toolchain.
+
 2000-08-08  Jeff Johnston <jjohnstn@redhat.com>
 
 	* libc/stdio/snprintf.c (snprintf, _snprintf_r): Fixed code
diff --git a/newlib/libc/sys/arm/setjmp.S b/newlib/libc/sys/arm/setjmp.S
index eab8e214a..562015445 100644
--- a/newlib/libc/sys/arm/setjmp.S
+++ b/newlib/libc/sys/arm/setjmp.S
@@ -3,58 +3,127 @@
    Nick Clifton, Cygnus Solutions, 13 June 1997.  */
 
 /* ANSI concatenation macros.  */
-#define CONCAT(a, b) CONCAT2(a, b)
-#define CONCAT2(a, b) a ## b
+#define CONCAT(a, b)  CONCAT2(a, b)
+#define CONCAT2(a, b) a##b
 
-#ifdef __USER_LABEL_PREFIX__
-#define FUNCTION( name ) CONCAT (__USER_LABEL_PREFIX__, name)
+#ifndef __USER_LABEL_PREFIX__
+#error  __USER_LABEL_PREFIX__ not defined
+#endif
+
+#define SYM(x) CONCAT (__USER_LABEL_PREFIX__, x)
+
+#ifdef __ELF__
+#define TYPE(x) .type SYM(x),function
+#define SIZE(x) .size SYM(x), . - SYM(x)
 #else
-#error __USER_LABEL_PREFIX__ is not defined
+#define TYPE(x)
+#define SIZE(x)
 #endif
+
+/* Arm/Thumb interworking support:
+
+   The interworking scheme expects functions to use a BX instruction
+   to return control to their parent.  Since we need this code to work
+   in both interworked and non-interworked environments as well as with
+   older processors which do not have the BX instruction we do the 
+   following:
+	Test the return address.
+	If the bottom bit is clear perform an "old style" function exit.
+	(We know that we are in ARM mode and returning to an ARM mode caller).
+	Otherwise use the BX instruction to perform the function exit.
+
+   We know that we will never attempt to perform the BX instruction on 
+   an older processor, because that kind of processor will never be 
+   interworked, and a return address with the bottom bit set will never 
+   be generated.
+
+   In addition, we do not actually assemble the BX instruction as this would
+   require us to tell the assembler that the processor is an ARM7TDMI and
+   it would store this information in the binary.  We want this binary to be
+   able to be linked with binaries compiled for older processors however, so
+   we do not want such information stored there.  
+
+   If we are running using the APCS-26 convention however, then we never
+   test the bottom bit, because this is part of the processor status.  
+   Instead we just do a normal return, since we know that we cannot be 
+   returning to a Thumb caller - the Thumb does not support APCS-26.
 	
+   Function entry is much simpler.  If we are compiling for the Thumb we 
+   just switch into ARM mode and then drop through into the rest of the
+   function.  The function exit code will take care of the restore to
+   Thumb mode.  */
 
-	.text
+#ifdef __APCS_26__
+#define RET	movs		pc, lr
+#else
+#define RET	tst		lr, #1; \
+	        moveq		pc, lr ; \
+.word           0xe12fff1e	/* bx lr */
+#endif
+
+#ifdef __thumb__
+#define	MODE		.thumb_func
+.macro PROLOGUE name
+	bx	pc
+	nop	
 	.code 32
+SYM (.arm_start_of.\name):
+.endm
+#else
+#define	MODE		.code 32
+.macro PROLOGUE name
+.endm
+#endif
+	
+.macro FUNC_START name
+	.text
 	.align 2
+	MODE
+	.globl SYM (\name)
+	TYPE (\name)
+SYM (\name):
+	PROLOGUE \name
+.endm
+
+.macro FUNC_END name
+	RET
+	SIZE (\name)
+.endm
+	
+/* --------------------------------------------------------------------
+                 int setjmp (jmp_buf); 
+   -------------------------------------------------------------------- */
 	
-/* int setjmp (jmp_buf);  */
-	.globl	FUNCTION(setjmp)
-FUNCTION(setjmp):
+	FUNC_START setjmp
 
-	/* Save all the callee-preserved registers into the jump buffer. */
+	/* Save all the callee-preserved registers into the jump buffer.  */
 	stmea		a1!, { v1-v7, fp, ip, sp, lr }
 	
-#if 0	/* Simulator does not cope with FP instructions yet.... */
+#if 0	/* Simulator does not cope with FP instructions yet.  */
 #ifndef __SOFTFP__
-	/* Save the floating point registers */
+	/* Save the floating point registers.  */
 	sfmea		f4, 4, [a1]
 #endif
 #endif		
-	/* When setting up the jump buffer return 0. */
+	/* When setting up the jump buffer return 0.  */
 	mov		a1, #0
 
-	/* Return to caller, see comment in longjmp below */
-#ifdef __APCS_26__
-	movs		pc, lr
-#else
-	tst		lr, #1
-	moveq		pc, lr
-.word   0xe12fff1e	/*  bx lr */
-#endif
+	FUNC_END setjmp
 	
+/* --------------------------------------------------------------------
+		volatile void longjmp (jmp_buf, int);
+   -------------------------------------------------------------------- */
+	
+	FUNC_START longjmp
 
-/* volatile void longjmp (jmp_buf, int);  */
-	.globl	FUNCTION(longjmp)
-FUNCTION(longjmp):
-
-	/* If we have stack extension code it ought to be handled here. */
+	/* If we have stack extension code it ought to be handled here.  */
 	
-	/* Restore the registers, retrieving the state when setjmp() was called. */
+	/* Restore the registers, retrieving the state when setjmp() was called.  */
 	ldmfd		a1!, { v1-v7, fp, ip, sp, lr }
 	
-#if 0	/* Simulator does not cope with FP instructions yet.... */
+#if 0	/* Simulator does not cope with FP instructions yet.  */
 #ifndef __SOFTFP__
-	/* Restore floating point registers as well */
+	/* Restore floating point registers as well.  */
 	lfmfd		f4, 4, [a1]
 #endif
 #endif	
@@ -63,40 +132,5 @@ FUNCTION(longjmp):
 	movs		a1, a2
 	moveq		a1, #1
 
-	/* Arm/Thumb interworking support:
-	
-	   The interworking scheme expects functions to use a BX instruction
-	   to return control to their parent.  Since we need this code to work
-	   in both interworked and non-interworked environments as well as with
-	   older processors which do not have the BX instruction we do the 
-	   following:
-		Test the return address.
-		If the bottom bit is clear perform an "old style" function exit.
-		(We know that we are in ARM mode and returning to an ARM mode caller).
-		Otherwise use the BX instruction to perform the function exit.
-	
-	   We know that we will never attempt to perform the BX instruction on 
-	   an older processor, because that kind of processor will never be 
-	   interworked, and a return address with the bottom bit set will never 
-	   be generated.
-
-	   In addition, we do not actually assemble the BX instruction as this would
-	   require us to tell the assembler that the processor is an ARM7TDMI and
-	   it would store this information in the binary.  We want this binary to be
-	   able to be linked with binaries compiled for older processors however, so
-	   we do not want such information stored there.  
-
-	   If we are running using the APCS-26 convention however, then we never
-	   test the bottom bit, because this is part of the processor status.  
-	   Instead we just do a normal return, since we know that we cannot be 
-	   returning to a Thumb caller - the Thumb doe snot support APCS-26
-	*/
-
-#ifdef __APCS_26__
-	movs		pc, lr
-#else
-	tst		lr, #1
-	moveq		pc, lr
-.word   0xe12fff1e	/* bx lr */
-#endif
+	FUNC_END longjmp