import newlib-2000-02-17 snapshot

1 files changed, 102 insertions, 0 deletions

diff --git a/newlib/libc/sys/arm/setjmp.S b/newlib/libc/sys/arm/setjmp.S
new file mode 100644
index 000000000..eab8e214a
--- /dev/null
+++ b/newlib/libc/sys/arm/setjmp.S
@@ -0,0 +1,102 @@
+/* This is a simple version of setjmp and longjmp.
+
+   Nick Clifton, Cygnus Solutions, 13 June 1997.  */
+
+/* ANSI concatenation macros.  */
+#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)
+#else
+#error __USER_LABEL_PREFIX__ is not defined
+#endif
+	
+
+	.text
+	.code 32
+	.align 2
+	
+/* int setjmp (jmp_buf);  */
+	.globl	FUNCTION(setjmp)
+FUNCTION(setjmp):
+
+	/* 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.... */
+#ifndef __SOFTFP__
+	/* Save the floating point registers */
+	sfmea		f4, 4, [a1]
+#endif
+#endif		
+	/* 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
+	
+
+/* volatile void longjmp (jmp_buf, int);  */
+	.globl	FUNCTION(longjmp)
+FUNCTION(longjmp):
+
+	/* If we have stack extension code it ought to be handled here. */
+	
+	/* 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.... */
+#ifndef __SOFTFP__
+	/* Restore floating point registers as well */
+	lfmfd		f4, 4, [a1]
+#endif
+#endif	
+	/* Put the return value into the integer result register.
+	   But if it is zero then return 1 instead.  */	
+	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
+