From cf2ee4ae2c6608261e849f0d75209669d435624c Mon Sep 17 00:00:00 2001
From: Koakuma <koachan@protonmail.com>
Date: Fri, 27 Nov 2020 18:51:50 +0700
Subject: [PATCH 1/3] Add sparc64 long double mapping

---
 src/stage1/codegen.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/stage1/codegen.cpp b/src/stage1/codegen.cpp
index 6a02f2912b..b449fb2fea 100644
--- a/src/stage1/codegen.cpp
+++ b/src/stage1/codegen.cpp
@@ -8640,6 +8640,9 @@ static void define_builtin_types(CodeGen *g) {
         case ZigLLVM_ppc64le:
             add_fp_entry(g, "c_longdouble", 128, LLVMFP128Type(), &g->builtin_types.entry_c_longdouble);
             break;
+        case ZigLLVM_sparcv9:
+            add_fp_entry(g, "c_longdouble", 128, LLVMFP128Type(), &g->builtin_types.entry_c_longdouble);
+            break;
         case ZigLLVM_avr:
             // It's either a float or a double, depending on a toolchain switch
             add_fp_entry(g, "c_longdouble", 64, LLVMDoubleType(), &g->builtin_types.entry_c_longdouble);

From 41c40f4bbec35ac260b6a7af6b0db0dafccb56ca Mon Sep 17 00:00:00 2001
From: Koakuma <koachan@protonmail.com>
Date: Fri, 27 Nov 2020 23:02:22 +0700
Subject: [PATCH 2/3] Fix fork() on Linux/sparc64

fork() on Linux/sparc64 seems to return its result in two registers,
with %o0 always holding the current process' PID, and the parent/child
status returned in %o1. Add some glue code to convert those into
the libc-style return value.
---
 lib/std/os/linux.zig         |  4 +++-
 lib/std/os/linux/sparc64.zig | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

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..20fdc275dd 100644
--- a/lib/std/os/linux/sparc64.zig
+++ b/lib/std/os/linux/sparc64.zig
@@ -21,6 +21,23 @@ pub fn syscall_pipe(fd: *[2]i32) usize {
     );
 }
 
+pub fn syscall_fork() usize {
+    return asm volatile (
+        \\ t 0x6d
+        \\ bcc,pt %%xcc, 1f
+        \\ nop
+        \\ ba 2f
+        \\ neg %%o0
+        \\ 1:
+        \\ 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

From f10bff9ffb452eaf22af8dd85412653ac8bd1081 Mon Sep 17 00:00:00 2001
From: Koakuma <koachan@protonmail.com>
Date: Sat, 28 Nov 2020 13:24:24 +0700
Subject: [PATCH 3/3] Add a comment to explain the fork return values on
 sparc64

---
 lib/std/os/linux/sparc64.zig | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/std/os/linux/sparc64.zig b/lib/std/os/linux/sparc64.zig
index 20fdc275dd..902940071e 100644
--- a/lib/std/os/linux/sparc64.zig
+++ b/lib/std/os/linux/sparc64.zig
@@ -22,6 +22,11 @@ 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
@@ -29,6 +34,7 @@ pub fn syscall_fork() usize {
         \\ ba 2f
         \\ neg %%o0
         \\ 1:
+        \\ # Clear the child's %%o0
         \\ dec %%o1
         \\ and %%o1, %%o0, %%o0
         \\ 2: