xtensa: support call0 ABI

Most changes are mechanical replacement of 'retw' instruction with
'abi_ret' macro, defined to 'retw' or 'ret' according to ABI.
Assembly code that makes calls is duplicated for call0 ABI with changed
register numbers for parameters/return value and call instruction.
'entry' instructions are replaced with 'abi_entry' macro.

More interesting changes:
- non-leaf assembly functions (e.g. _dl_tlsdesc_dynamic,
  _dl_linux_resolve, SYSCALL_ERROR_HANDLER, PSEUDO) now need to preserve
  registers around intermediate calls they make, use temporary stack
  frame for that;
- setjmp/longjmp only need to save and restore return address, stack
  pointer and callee-saved registers in the jmpbuf;
- __clone and syscall functions had hardcoded offsets to parameter
  passed on stack, on call0 ABI they don't need stack frame, so the
  offset is different. Replace these offsets with FRAMESIZE macro.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/libc/string/xtensa/strcmp.S b/libc/string/xtensa/strcmp.S
index 8ed1ed009..2dce590db 100644
--- a/libc/string/xtensa/strcmp.S
+++ b/libc/string/xtensa/strcmp.S
@@ -108,7 +108,7 @@ ENTRY (strcmp)
 #endif
 .Lretdiff:
 	sub	a2, a8, a9
-	retw
+	abi_ret
 
 /* s1 is word-aligned; s2 is word-aligned.
 
@@ -229,7 +229,7 @@ ENTRY (strcmp)
 
 	/* Words are equal; some byte is zero.  */
 .Leq:	movi	a2, 0		/* return equal */
-	retw
+	abi_ret
 
 .Lwne2:	/* Words are not equal.  On big-endian processors, if none of the
 	   bytes are zero, the return value can be determined by a simple
@@ -239,10 +239,10 @@ ENTRY (strcmp)
 	bnall	a10, a7, .Lsomezero
 	bgeu	a8, a9, .Lposreturn
 	movi	a2, -1
-	retw
+	abi_ret
 .Lposreturn:
 	movi	a2, 1
-	retw
+	abi_ret
 .Lsomezero:	/* There is probably some zero byte. */
 #endif /* __XTENSA_EB__ */
 .Lwne:	/* Words are not equal.  */
@@ -263,14 +263,14 @@ ENTRY (strcmp)
 	   byte.  Just subtract words to get the return value.
 	   The high order equal bytes cancel, leaving room for the sign.  */
 	sub	a2, a8, a9
-	retw
+	abi_ret
 
 .Ldiff0:
 	/* Need to make room for the sign, so can't subtract whole words.  */
 	extui	a10, a8, 24, 8
 	extui	a11, a9, 24, 8
 	sub	a2, a10, a11
-	retw
+	abi_ret
 
 #else /* !__XTENSA_EB__ */
 	/* Little-endian is a little more difficult because can't subtract
@@ -281,28 +281,28 @@ ENTRY (strcmp)
 	extui	a10, a8, 24, 8
 	extui	a11, a9, 24, 8
 	sub	a2, a10, a11
-	retw
+	abi_ret
 
 .Ldiff0:
 	/* Byte 0 is different.  */
 	extui	a10, a8, 0, 8
 	extui	a11, a9, 0, 8
 	sub	a2, a10, a11
-	retw
+	abi_ret
 
 .Ldiff1:
 	/* Byte 0 is equal; byte 1 is different.  */
 	extui	a10, a8, 8, 8
 	extui	a11, a9, 8, 8
 	sub	a2, a10, a11
-	retw
+	abi_ret
 
 .Ldiff2:
 	/* Bytes 0-1 are equal; byte 2 is different.  */
 	extui	a10, a8, 16, 8
 	extui	a11, a9, 16, 8
 	sub	a2, a10, a11
-	retw
+	abi_ret
 
 #endif /* !__XTENSA_EB */