zig

commit ba9ab3fb6720ff5894ac07741eccaaca44122eb0 (tree)
parent eb36a45ed9fbdf5ab92c3cdb650375a13eaaa648
Author: Alex Rønne Petersen <alex@alexrp.com>
Date:   Thu, 16 Oct 2025 17:09:30 +0200

std.debug: add CPU context and DWARF mappings for m68k

Diffstat:
M
lib/std/debug/Dwarf.zig
 | 
3
+++
M
lib/std/debug/SelfInfo/Elf.zig
 | 
9
++++++---
M
lib/std/debug/cpu_context.zig
 | 
40
++++++++++++++++++++++++++++++++++++++++

3 files changed, 49 insertions(+), 3 deletions(-)
diff --git a/lib/std/debug/Dwarf.zig b/lib/std/debug/Dwarf.zig
@@ -1435,6 +1435,7 @@ pub fn ipRegNum(arch: std.Target.Cpu.Arch) ?u16 {
         .hexagon => 76,
         .lanai => 2,
         .loongarch32, .loongarch64 => 64,
+        .m68k => 26,
         .mips, .mipsel, .mips64, .mips64el => 66,
         .or1k => 35,
         .powerpc, .powerpcle, .powerpc64, .powerpc64le => 67,
@@ -1456,6 +1457,7 @@ pub fn fpRegNum(arch: std.Target.Cpu.Arch) u16 {
         .hexagon => 30,
         .lanai => 5,
         .loongarch32, .loongarch64 => 22,
+        .m68k => 14,
         .mips, .mipsel, .mips64, .mips64el => 30,
         .or1k => 2,
         .powerpc, .powerpcle, .powerpc64, .powerpc64le => 1,
@@ -1477,6 +1479,7 @@ pub fn spRegNum(arch: std.Target.Cpu.Arch) u16 {
         .hexagon => 29,
         .lanai => 4,
         .loongarch32, .loongarch64 => 3,
+        .m68k => 15,
         .mips, .mipsel, .mips64, .mips64el => 29,
         .or1k => 1,
         .powerpc, .powerpcle, .powerpc64, .powerpc64le => 1,
diff --git a/lib/std/debug/SelfInfo/Elf.zig b/lib/std/debug/SelfInfo/Elf.zig
@@ -94,19 +94,21 @@ pub const can_unwind: bool = s: {
     // Notably, we are yet to support unwinding on ARM. There, unwinding is not done through
     // `.eh_frame`, but instead with the `.ARM.exidx` section, which has a different format.
     const archs: []const std.Target.Cpu.Arch = switch (builtin.target.os.tag) {
-        // Not supported yet: arm, m68k
+        // Not supported yet: arm
         .haiku => &.{
             .aarch64,
+            .m68k,
             .riscv64,
             .x86,
             .x86_64,
         },
-        // Not supported yet: arc, arm/armeb/thumb/thumbeb, m68k, xtensa
+        // Not supported yet: arc, arm/armeb/thumb/thumbeb, xtensa
         .linux => &.{
             .aarch64,
             .aarch64_be,
             .csky,
             .loongarch64,
+            .m68k,
             .mips,
             .mipsel,
             .mips64,
@@ -133,10 +135,11 @@ pub const can_unwind: bool = s: {
             .riscv64,
             .x86_64,
         },
-        // Not supported yet: arm/armeb, m68k, mips64/mips64el
+        // Not supported yet: arm/armeb, mips64/mips64el
         .netbsd => &.{
             .aarch64,
             .aarch64_be,
+            .m68k,
             .mips,
             .mipsel,
             .x86,
diff --git a/lib/std/debug/cpu_context.zig b/lib/std/debug/cpu_context.zig
@@ -10,6 +10,7 @@ else switch (native_arch) {
     .hexagon => Hexagon,
     .lanai => Lanai,
     .loongarch32, .loongarch64 => LoongArch,
+    .m68k => M68k,
     .mips, .mipsel, .mips64, .mips64el => Mips,
     .or1k => Or1k,
     .powerpc, .powerpcle, .powerpc64, .powerpc64le => Powerpc,
@@ -87,6 +88,11 @@ pub fn fromPosixSignalContext(ctx_ptr: ?*const anyopaque) ?Native {
             .r = uc.mcontext.r,
             .pc = uc.mcontext.pc,
         },
+        .m68k => .{
+            .d = uc.mcontext.d,
+            .a = uc.mcontext.a,
+            .pc = uc.mcontext.pc,
+        },
         .powerpc, .powerpcle, .powerpc64, .powerpc64le => .{
             .r = uc.mcontext.r,
             .pc = uc.mcontext.pc,
@@ -698,6 +704,40 @@ const LoongArch = extern struct {
 };
 
 /// This is an `extern struct` so that inline assembly in `current` can use field offsets.
+const M68k = extern struct {
+    /// The numbered data registers d0 - d7.
+    d: [8]u32,
+    /// The numbered address registers a0 - a7.
+    a: [8]u32,
+    pc: u32,
+
+    pub inline fn current() M68k {
+        var ctx: M68k = undefined;
+        asm volatile (
+            \\ movem.l %%d0 - %%a7, (%%a0)
+            \\ lea.l (%%pc), %%a1
+            \\ move.l %%a1, (%%a0, 64)
+            :
+            : [ctx] "{a0}" (&ctx),
+            : .{ .a1 = true, .memory = true });
+        return ctx;
+    }
+
+    pub fn dwarfRegisterBytes(ctx: *M68k, register_num: u16) DwarfRegisterError![]u8 {
+        switch (register_num) {
+            0...7 => return @ptrCast(&ctx.d[register_num]),
+            8...15 => return @ptrCast(&ctx.a[register_num - 8]),
+            26 => return @ptrCast(&ctx.pc),
+
+            16...23 => return error.UnsupportedRegister, // fp0 - fp7
+            24...25 => return error.UnsupportedRegister, // Return columns in GCC...?
+
+            else => return error.InvalidRegister,
+        }
+    }
+};
+
+/// This is an `extern struct` so that inline assembly in `current` can use field offsets.
 const Mips = extern struct {
     /// The numbered general-purpose registers r0 - r31. r0 must be zero.
     r: [32]Gpr,