stormy-abi: Document abi changes.

        * config/stormy16/stormy-abi:  Document abi changes.
        * config/stormy16/stormy16.h (REG_ALLOC_ORDER): Redefine.
        (ICALL_REGS): New register class.
        (NUM_ARGUMENT_REGISTERS): Now 6.
        (DEFAULT_PCC_STRUCT_RETURN): Don't try to return structs
        in registers.
        (REG_CLASS_FROM_LETTER): Map 'z' to ICALL_REGS.
        * config/stormy16.md (call_internal, call_value_internal,
        indirect_jump): Use new 'z' constraint.

From-SVN: r46041

gcc/ChangeLog

+2001-10-05  Catherine Moore  <clm@redhat.com>
+
+        * config/stormy16/stormy-abi:  Document abi changes.
+        * config/stormy16/stormy16.h (REG_ALLOC_ORDER): Redefine.
+        (ICALL_REGS): New register class.
+        (NUM_ARGUMENT_REGISTERS): Now 6.
+        (DEFAULT_PCC_STRUCT_RETURN): Don't try to return structs
+        in registers.
+        (REG_CLASS_FROM_LETTER): Map 'z' to ICALL_REGS.
+        * config/stormy16.md (call_internal, call_value_internal,
+        indirect_jump): Use new 'z' constraint.
+
 2001-10-05  Neil Booth  <neil@daikokuya.demon.co.uk>
 
 	* doc/cppinternals.texi: Update.

gcc/config/stormy16/stormy-abi

@@ -24,17 +24,19 @@ The registers are allocated as follows:
 
 Register	Purpose
 -------------------------------------------------------------------
-r0, r1		Call-volatile.  May be changed during the execution
+r0, r1          Call-volatile.  May be changed during the execution
+                of a call instruction.
+r2 through r7   Argument passing;  call-clobbered.
+r8, r9		Call-volatile.  May be changed during the execution
 		of a call instruction.
-r2 through r9	Argument passing; call-clobbered.
 r10 through r13	Call-saved.
 r14		Program status word.
 r15		Stack pointer.
 
 
-The return value of a procedure is returned in r2-r9 if it fits,
-otherwise a pointer is passed as a `hidden' first argument
-and the return value is placed there.
+Scalar values are returned in register r2-r7 if the value fits.
+Otherwise, a pointer is passed as a 'hidden' first argument and
+the return value is placed there.
 
 Arguments are passed in registers starting in r2, then on the stack.
 Arguments of size not a multiple of a word are padded to whole words.
@@ -83,20 +85,18 @@ count += N;
 
 
 One implementation of this is if a variadic function first
-pushes registers 2 through 9 in sequence at entry, and
+pushes registers 2 through 7 in sequence at entry, and
 sets 'base' to the address of the first word pushed, 
 producing a stack that appears like:
 
 SP ->
 	[other data]
-	r9
-	r8
 	r7
 	r6
 	r5
 	r4
 	r3
-count-> r2
+count->	r2
 	Return address (two words)
 	9th procedure parameter word
 	10th procedure parameter word

gcc/config/stormy16/stormy16.h

@@ -1043,7 +1043,7 @@ do {									\
    only sequences of consecutive registers.  On such machines, define
    `REG_ALLOC_ORDER' to be an initializer that lists the highest numbered
    allocatable register first.  */
-#define REG_ALLOC_ORDER { 9, 7, 6, 5, 4, 3, 8, 2, 1, 0, 10, 11, 12, 13, 14, 15, 16 }
+#define REG_ALLOC_ORDER { 7, 6, 5, 4, 3, 2, 1, 0, 9, 8, 10, 11, 12, 13, 14, 15, 16 }
 
 /* A C statement (sans semicolon) to choose the order in which to allocate hard
    registers for pseudo-registers local to a basic block.
@@ -1204,6 +1204,7 @@ enum reg_class
   R2_REGS,
   EIGHT_REGS,
   R8_REGS,
+  ICALL_REGS,
   GENERAL_REGS,
   CARRY_REGS,
   ALL_REGS,
@@ -1226,6 +1227,7 @@ enum reg_class
   "R2_REGS",					\
   "EIGHT_REGS",					\
   "R8_REGS",					\
+  "ICALL_REGS",					\
   "GENERAL_REGS",				\
   "CARRY_REGS",					\
   "ALL_REGS"					\
@@ -1250,6 +1252,7 @@ enum reg_class
   0x00004,					\
   0x000FF,					\
   0x00100,					\
+  0x00300,					\
   0x6FFFF,					\
   0x10000,					\
   (1 << FIRST_PSEUDO_REGISTER) - 1		\
@@ -1303,6 +1306,7 @@ enum reg_class
   : (CHAR) == 'e' ? EIGHT_REGS			\
   : (CHAR) == 't' ? TWO_REGS			\
   : (CHAR) == 'y' ? CARRY_REGS			\
+  : (CHAR) == 'z' ? ICALL_REGS			\
   : NO_REGS)
 
 /* A C expression which is nonzero if register number NUM is suitable for use
@@ -2007,7 +2011,7 @@ enum reg_class
 
 /* Function Arguments in Registers */
 
-#define NUM_ARGUMENT_REGISTERS 8
+#define NUM_ARGUMENT_REGISTERS 6
 #define FIRST_ARGUMENT_REGISTER 2
 
 #define STORMY16_WORD_SIZE(TYPE, MODE)				\
@@ -2293,7 +2297,7 @@ typedef int CUMULATIVE_ARGS;
    return values are decided by the `RETURN_IN_MEMORY' macro.
 
    If not defined, this defaults to the value 1.  */
-#define DEFAULT_PCC_STRUCT_RETURN 0
+/* #define DEFAULT_PCC_STRUCT_RETURN 0 */
 
 /* If the structure value address is passed in a register, then
    `STRUCT_VALUE_REGNUM' should be the number of that register.  */

gcc/config/stormy16/stormy16.md

@@ -822,7 +822,7 @@
 (define_insn "*call_internal"
   [(call (mem:HI (match_operand:HI 0 "nonmemory_operand" "i,r"))
 	 (match_operand 1 "" ""))
-   (use (match_operand:HI 2 "nonmemory_operand" "X,t"))]
+   (use (match_operand:HI 2 "nonmemory_operand" "X,z"))]
   ""
   "@
    callf %C0
@@ -834,7 +834,7 @@
   [(set (match_operand 3 "register_operand" "=r,r")
         (call (mem:HI (match_operand:HI 0 "nonmemory_operand" "i,r"))
 	      (match_operand 1 "" "")))
-   (use (match_operand:HI 2 "nonmemory_operand" "X,t"))]
+   (use (match_operand:HI 2 "nonmemory_operand" "X,z"))]
   ""
   "@
    callf %C0
@@ -882,7 +882,7 @@
 
 (define_insn ""
   [(set (pc) (match_operand:HI 0 "register_operand" "r"))
-   (use (match_operand:HI 1 "register_operand" "t"))]
+   (use (match_operand:HI 1 "register_operand" "z"))]
   ""
   "jmp %1,%0"
   [(set_attr "length" "4")