Merge pull request ziglang#21608 from mikdusan/ppc64

ppc64: get further along into system bootstrap

Author: alexrp

lib/std/os/linux/powerpc64.zig

@@ -48,7 +48,7 @@ pub fn syscall2(number: SYS, arg1: usize, arg2: usize) usize {
         : [number] "{r0}" (@intFromEnum(number)),
           [arg1] "{r3}" (arg1),
           [arg2] "{r4}" (arg2),
-        : "memory", "cr0", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"
+        : "memory", "cr0", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"
     );
 }
 
@@ -63,7 +63,7 @@ pub fn syscall3(number: SYS, arg1: usize, arg2: usize, arg3: usize) usize {
           [arg1] "{r3}" (arg1),
           [arg2] "{r4}" (arg2),
           [arg3] "{r5}" (arg3),
-        : "memory", "cr0", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"
+        : "memory", "cr0", "r6", "r7", "r8", "r9", "r10", "r11", "r12"
     );
 }
 
@@ -79,7 +79,7 @@ pub fn syscall4(number: SYS, arg1: usize, arg2: usize, arg3: usize, arg4: usize)
           [arg2] "{r4}" (arg2),
           [arg3] "{r5}" (arg3),
           [arg4] "{r6}" (arg4),
-        : "memory", "cr0", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"
+        : "memory", "cr0", "r7", "r8", "r9", "r10", "r11", "r12"
     );
 }
 
@@ -96,7 +96,7 @@ pub fn syscall5(number: SYS, arg1: usize, arg2: usize, arg3: usize, arg4: usize,
           [arg3] "{r5}" (arg3),
           [arg4] "{r6}" (arg4),
           [arg5] "{r7}" (arg5),
-        : "memory", "cr0", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"
+        : "memory", "cr0", "r8", "r9", "r10", "r11", "r12"
     );
 }
 
@@ -122,7 +122,7 @@ pub fn syscall6(
           [arg4] "{r6}" (arg4),
           [arg5] "{r7}" (arg5),
           [arg6] "{r8}" (arg6),
-        : "memory", "cr0", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"
+        : "memory", "cr0", "r9", "r10", "r11", "r12"
     );
 }
 

lib/std/start.zig

@@ -391,6 +391,7 @@ fn _start() callconv(.Naked) noreturn {
             \\ stdu 0, -32(1)
             \\ mtlr 0
             \\ b %[posixCallMainAndExit]
+            \\ nop
             ,
             .s390x =>
             // Set up the stack frame (register save area and cleared back-chain slot).