Thread has a lot of assembly in it that you may find helpful to disect. Here’s a snippet:
fn freeAndExit(self: *ThreadCompletion) noreturn {
switch (target.cpu.arch) {
.x86 => asm volatile (
\\ movl $91, %%eax
\\ movl %[ptr], %%ebx
\\ movl %[len], %%ecx
\\ int $128
\\ movl $1, %%eax
\\ movl $0, %%ebx
\\ int $128
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),
.x86_64 => asm volatile (
\\ movq $11, %%rax
\\ syscall
\\ movq $60, %%rax
\\ movq $1, %%rdi
\\ syscall
:
: [ptr] "{rdi}" (@intFromPtr(self.mapped.ptr)),
[len] "{rsi}" (self.mapped.len),
),
.arm, .armeb, .thumb, .thumbeb => asm volatile (
\\ mov r7, #91
\\ mov r0, %[ptr]
\\ mov r1, %[len]
\\ svc 0
\\ mov r7, #1
\\ mov r0, #0
\\ svc 0
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),
.aarch64, .aarch64_be, .aarch64_32 => asm volatile (
\\ mov x8, #215
\\ mov x0, %[ptr]
\\ mov x1, %[len]
\\ svc 0
\\ mov x8, #93
\\ mov x0, #0
\\ svc 0
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),
.mips, .mipsel => asm volatile (
\\ move $sp, $25
\\ li $2, 4091
\\ move $4, %[ptr]
\\ move $5, %[len]
\\ syscall
\\ li $2, 4001
\\ li $4, 0
\\ syscall
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),
.mips64, .mips64el => asm volatile (
\\ li $2, 4091
\\ move $4, %[ptr]
\\ move $5, %[len]
\\ syscall
\\ li $2, 4001
\\ li $4, 0
\\ syscall
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),
.powerpc, .powerpcle, .powerpc64, .powerpc64le => asm volatile (
\\ li 0, 91
\\ mr %[ptr], 3
\\ mr %[len], 4
\\ sc
\\ li 0, 1
\\ li 3, 0
\\ sc
\\ blr
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),
.riscv64 => asm volatile (
\\ li a7, 215
\\ mv a0, %[ptr]
\\ mv a1, %[len]
\\ ecall
\\ li a7, 93
\\ mv a0, zero
\\ ecall
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),
.sparc64 => asm volatile (
\\ # SPARCs really don't like it when active stack frames
\\ # is unmapped (it will result in a segfault), so we
\\ # force-deactivate it by running `restore` until
\\ # all frames are cleared.
\\ 1:
\\ cmp %%fp, 0
\\ beq 2f
\\ nop
\\ ba 1b
\\ restore
\\ 2:
\\ mov 73, %%g1
\\ mov %[ptr], %%o0
\\ mov %[len], %%o1
\\ # Flush register window contents to prevent background
\\ # memory access before unmapping the stack.
\\ flushw
\\ t 0x6d
\\ mov 1, %%g1
\\ mov 1, %%o0
\\ t 0x6d
:
: [ptr] "r" (@intFromPtr(self.mapped.ptr)),
[len] "r" (self.mapped.len),
: "memory"
),