Merge pull request #7237 from koachan/sparc64-longdouble_fork

Add "long double" mapping and implement fork() on Linux/sparc64

2 files changed, 26 insertions, 1 deletions

diff --git a/lib/std/os/linux.zig b/lib/std/os/linux.zig
index 56e9d45a08..dbb9225aa2 100644
--- a/lib/std/os/linux.zig
+++ b/lib/std/os/linux.zig
@@ -112,7 +112,9 @@ pub fn execve(path: [*:0]const u8, argv: [*:null]const ?[*:0]const u8, envp: [*:
 }
 
 pub fn fork() usize {
-    if (@hasField(SYS, "fork")) {
+    if (comptime builtin.arch.isSPARC()) {
+        return syscall_fork();
+    } else if (@hasField(SYS, "fork")) {
         return syscall0(.fork);
     } else {
         return syscall2(.clone, SIGCHLD, 0);
diff --git a/lib/std/os/linux/sparc64.zig b/lib/std/os/linux/sparc64.zig
index eefa4d60fd..902940071e 100644
--- a/lib/std/os/linux/sparc64.zig
+++ b/lib/std/os/linux/sparc64.zig
@@ -21,6 +21,29 @@ pub fn syscall_pipe(fd: *[2]i32) usize {
     );
 }
 
+pub fn syscall_fork() usize {
+    // Linux/sparc64 fork() returns two values in %o0 and %o1:
+    // - On the parent's side, %o0 is the child's PID and %o1 is 0.
+    // - On the child's side, %o0 is the parent's PID and %o1 is 1.
+    // We need to clear the child's %o0 so that the return values
+    // conform to the libc convention.
+    return asm volatile (
+        \\ t 0x6d
+        \\ bcc,pt %%xcc, 1f
+        \\ nop
+        \\ ba 2f
+        \\ neg %%o0
+        \\ 1:
+        \\ # Clear the child's %%o0
+        \\ dec %%o1
+        \\ and %%o1, %%o0, %%o0
+        \\ 2:
+        : [ret] "={o0}" (-> usize)
+        : [number] "{g1}" (@enumToInt(SYS.fork))
+        : "memory", "xcc", "o1", "o2", "o3", "o4", "o5", "o7"
+    );
+}
+
 pub fn syscall0(number: SYS) usize {
     return asm volatile (
         \\ t 0x6d