restracturing to platform

.gitignore

@@ -0,0 +1,6 @@
+**/*.o
+**/*.a
+**/*.lds
+**/*.h
+zig-out/
+zig-cache/

build-cosmo.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+zig build-obj ./src/platform/cosmopolitan/main.zig -fno-PIE -fno-PIC -fno-stack-check --mod nmvm::src/nmvm.zig --deps nmvm
+ld.bfd main.o -o zig-out/bin/nmvm.com.dbg -T extern/cosmopolitan/ape.lds extern/cosmopolitan/crt.o extern/cosmopolitan/ape-copy-self.o \
+    extern/cosmopolitan/cosmopolitan.a -z common-page-size=0x1000 -z max-page-size=0x1000 --gc-sections

extern/cosmopolitan/get.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+wget wget https://justine.lol/cosmopolitan/cosmopolitan.tar.gz
+unzip cosmopolitan.tar.gz

extern/get.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+cd ./cosmopolitan
+./get.sh

gdb.sh

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-gdb ./zig-out/bin/nmvm -ex 'b arch.x86-64.execute' -ex 'layout asm' -ex 'r'
+gdb ./zig-out/bin/nmvm -ex 'b arch.x86-64.jedino-jedro.execute' -ex 'layout asm' -ex 'r'

prepare.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+cd ./extern
+./get.sh
+
+cd ../
+zig translate-c ./extern/cosmopolitan/cosmopolitan.h > ./src/platform/cosmopolitan/cosmopolitan.zig

src/arch/x86-64.zig

@@ -1,126 +1,2 @@
-// todo: Use r12, r13, ... instead? They're preserved in Sys V abi which might make it more confortable,
-//       but they might increase binary size, gotta test.
-
-// todo: Try using something else that has lesser opcode size.
-// Execution thread convention:
-// r12 <- binary thread pointer
-// r13 <- return stack pointer
-
-// Resources used:
-// https://mort.coffee/home/fast-interpreters/
-// https://blog.reverberate.org/2021/04/21/musttail-efficient-interpreters.html
-// https://en.wikibooks.org/wiki/X86_Assembly/GNU_assembly_syntax
-// https://www.cs.princeton.edu/courses/archive/spr18/cos217/lectures/15_AssemblyFunctions.pdf
-// https://ziglang.org/documentation/master/#toc-Assembly
-// https://csiflabs.cs.ucdavis.edu/~ssdavis/50/att-syntax.htm
-
-pub const Word = u64;
-pub const RecursionLimit = 1024;
-
-threadlocal var return_stack: [RecursionLimit + 1]Word = undefined;
-
-// todo: Variant that pushes array of words.
-/// (iw | -- iw)
-pub fn opPushWord() callconv(.Naked) noreturn {
-    asm volatile (
-        \\ add $0x10, %%r12
-        \\ pushq -8(%%r12)
-        \\ jmpq *(%%r12)
-    );
-}
-
-// todo: Variant that discards array of words.
-/// (w --)
-pub fn opSinkWord() callconv(.Naked) noreturn {
-    asm volatile (
-        \\ add $0x08, %%r12
-        \\ addq $0x08, %%rsp
-        \\ jmpq *(%%r12)
-    );
-}
-
-/// (iw | -- (iw'nth word from stack) )
-// fn opTakeWord(binary: [*]const Word, cond: bool) noreturn {
-//     @setRuntimeSafety(false);
-//     takeWord(binary[1].word);
-//     @call(.always_tail, binary[2].function, .{ &binary[2], cond });
-// }
-
-/// (iw | w)
-// fn opSetWord(binary: [*]const Word, cond: bool) noreturn {
-//     @setRuntimeSafety(false);
-//     setWord(binary[1].word, popWord());
-//     @call(.always_tail, binary[2].function, .{ &binary[2], cond });
-// }
-
-// todo: Generate operation permutations procedurally.
-// todo: Jump on overflow instead of cond setting?
-/// (w1 w2 -- sum overflow)
-pub fn opSumWordsWithOverflow() callconv(.Naked) noreturn {
-    // https://www.felixcloutier.com/x86/adc
-    // https://www.felixcloutier.com/x86/setcc
-    // idea: Could https://www.felixcloutier.com/x86/cmovcc be better for overflow push?
-    asm volatile (
-        \\ addq $0x08, %%r12
-        \\ movq (%%rsp), %%rax
-        \\ adcq 8(%%rsp), %%rax
-        \\ movq %%rax, 8(%%rsp)
-        \\ setc %%al
-        \\ movb %%al, (%%rsp)
-        \\ jmpq *(%%r12)
-    );
-}
-
-// todo: Generate operation permutations procedurally.
-// todo: We might not need cond register if conditions and jumps are combined?
-/// (w1 w2)
-// fn opRelativeJumpIfGreaterThan(binary: [*]const Word, cond: bool) noreturn {
-//     @setRuntimeSafety(false);
-//     const offset = if (popWord() > popWord()) binary[1].word else 2;
-//     @call(.always_tail, binary[offset].function, .{ &binary[offset], cond });
-// }
-
-// todo: Complex call op that would receive immediate mask that would tell
-//       which positions of stack to duplicate, as well as mixing of plain immediate operands.
-//       Or we could decouple it from call, it might be useful at other places.
-/// (iw |)
-pub fn opCall() callconv(.Naked) noreturn {
-    asm volatile (
-        \\ leaq 16(%%r12), %%rax
-        \\ subq $0x8, %%r13
-        \\ movq %%rax, (%%r13)
-        \\ movq 8(%%r12), %%r12
-        \\ jmpq *(%%r12)
-    );
-}
-
-/// (addr)
-pub fn opReturn() callconv(.Naked) noreturn {
-    asm volatile (
-        \\ movq (%%r13), %%r12
-        \\ addq $0x08, %%r13
-        \\ jmpq *(%%r12)
-    );
-}
-
-// todo: Make sure it's non reentry in one given thread.
-pub fn execute(binary: []const Word, entry_addr: usize) void {
-    @setCold(true);
-    // todo: Ensure correctness.
-    // https://wiki.osdev.org/System_V_ABI
-
-    // todo: Use remaining stack as return.
-
-    // Such device is used so that opReturn could be used for return.
-    asm volatile (
-        \\     movq $0f, 8(%%r13)
-        \\     leaq 8(%%r13), %%rax
-        \\     movq %%rax, (%%r13)
-        \\     jmpq *(%%r12)
-        \\ 0:
-        :
-        : [thread] "r" (&binary[entry_addr]),
-          [retstk] "r" (&return_stack[return_stack.len - 2]),
-        : "rflags", "rax", "rbx", "rsp", "rdi", "rbp", "r14", "r15", "rsi", "rdx", "rcx", "r8", "r9", "r10", "r11", "memory"
-    );
-}
+pub usingnamespace @import("x86-64/jedino-jedro.zig");
+pub usingnamespace @import("x86-64/zov/ve-sistema.zig");

src/arch/x86-64/jedino-jedro.zig

@@ -0,0 +1,181 @@
+//! jedino jedro (.jj:x86-64)
+//!
+//! Desired properties:
+//! - OS agnosticism, meaning it tries to respect conventions posed by target OSes.
+//!   For extensions based open it there should be an enum value indicating host,
+//!   for example, when dealing with extern C functions of shared objects.
+//!   Stack/thread pointers are chosen so that SysV and MS abis callee side preserve those,
+//!   so that we don't need to constantly push and restore on procedure call.
+
+// Execution thread convention:
+// r12 <- binary thread pointer
+// r13 <- return stack pointer
+// r14 <- extension context pointer
+
+// todo: Use ZF flag as conditional register so to not involve stack?
+//       Alternatively we could keep boolean word, but implement it in vector semantics.
+//
+//       ZF flag route can be achieved with using LEA instead of ADD as it doesn't touch flags,
+//       but we would need to store the flag when doing other calling convention calls.
+
+// Resources:
+// https://mort.coffee/home/fast-interpreters/
+// https://blog.reverberate.org/2021/04/21/musttail-efficient-interpreters.html
+// https://en.wikibooks.org/wiki/X86_Assembly/GNU_assembly_syntax
+// https://www.cs.princeton.edu/courses/archive/spr18/cos217/lectures/15_AssemblyFunctions.pdf
+// https://ziglang.org/documentation/master/#toc-Assembly
+// https://csiflabs.cs.ucdavis.edu/~ssdavis/50/att-syntax.htm
+// https://stackoverflow.com/questions/37639993/is-this-assembly-function-call-safe-complete
+// https://groups.csail.mit.edu/pag/OLD/parg/piumarta98optimizing.pdf
+// https://dl.acm.org/doi/pdf/10.1145/1328195.1328197
+// https://www.agner.org/optimize/instruction_tables.pdf
+// https://stackoverflow.com/questions/6323027/lea-or-add-instruction
+
+// Neat things:
+// https://joryanick.com/retro-fast-x86-memcpy.php
+// https://www.codeproject.com/Articles/1110153/Apex-memmove-the-fastest-memcpy-memmove-on-x-x-EVE
+// https://www.usenix.org/legacy/publications/library/proceedings/jvm01/gagnon/gagnon_html/node19.html#piumarta
+// https://www.agner.org/optimize/optimizing_assembly.pdf
+// http://sebastianmihai.com/x86-assembly-optimization.html
+
+// todo: Opcode for fast integer divisions with statically known divider.
+// todo: Opcodes taking operands based on offset from top of stack, without consuming.
+// todo: Certain constant multiplication optimization by LEA:
+//   LEA EAX, [EAX * 2 + EAX]   ;EAX = EAX * 3
+//   LEA EAX, [EAX * 4 + EAX]   ;EAX = EAX * 5
+//   LEA EAX, [EAX * 8 + EAX]   ;EAX = EAX * 9
+//
+
+const tolmac = @import("../../tolmac.zig");
+const Word = tolmac.Word;
+
+// todo: Variant that pushes array of words.
+/// (iw | -- iw)
+pub fn opPushWord() callconv(.Naked) noreturn {
+    asm volatile (
+        \\ addq $0x10, %%r12
+        \\ pushq -8(%%r12)
+        \\ jmpq *(%%r12)
+    );
+}
+
+// todo: Variant that discards array of words.
+/// (w)
+pub fn opSinkWord() callconv(.Naked) noreturn {
+    asm volatile (
+        \\ addq $0x08, %%r12
+        \\ addq $0x08, %%rsp
+        \\ jmpq *(%%r12)
+    );
+}
+
+/// (iw | -- (iw'nth word from stack) )
+// fn opTakeWord(binary: [*]const Word, cond: bool) noreturn {
+//     @setRuntimeSafety(false);
+//     takeWord(binary[1].word);
+//     @call(.always_tail, binary[2].function, .{ &binary[2], cond });
+// }
+
+/// (iw | w)
+// fn opSetWord(binary: [*]const Word, cond: bool) noreturn {
+//     @setRuntimeSafety(false);
+//     setWord(binary[1].word, popWord());
+//     @call(.always_tail, binary[2].function, .{ &binary[2], cond });
+// }
+
+/// (w1 w2 -- sum overflow)
+pub fn opSumWordsWithOverflow() callconv(.Naked) noreturn {
+    // https://www.felixcloutier.com/x86/add
+    // https://www.felixcloutier.com/x86/setcc
+    asm volatile (
+        \\ addq $0x08, %%r12
+        \\ movq (%%rsp), %%rbx
+        \\ movq %%rbx, %%rax
+        \\ addq 8(%%rsp), %%rax
+        \\ movq %%rax, 8(%%rsp)
+        \\ xorq %%rbx, (%%rsp)
+        \\ setc (%%rsp)
+        \\ jmpq *(%%r12)
+    );
+}
+
+/// (w1 w2 -- sum)
+pub fn opSumWords() callconv(.Naked) noreturn {
+    asm volatile (
+        \\ addq $0x08, %%r12
+        \\ popq %%rax
+        \\ addq (%%rsp), %%rax
+        \\ movq %%rax, (%%rsp)
+        \\ jmpq *(%%r12)
+    );
+}
+
+// todo: Generate operation permutations procedurally.
+// todo: We might not need cond register if conditions and jumps are combined?
+/// (w1 w2)
+// fn opRelativeJumpIfGreaterThan(binary: [*]const Word, cond: bool) noreturn {
+//     @setRuntimeSafety(false);
+//     const offset = if (popWord() > popWord()) binary[1].word else 2;
+//     @call(.always_tail, binary[offset].function, .{ &binary[offset], cond });
+// }
+
+/// (iw |)
+pub fn opCall() callconv(.Naked) noreturn {
+    asm volatile (
+        \\ leaq 16(%%r12), %%rax
+        \\ subq $0x8, %%r13
+        \\ movq %%rax, (%%r13)
+        \\ movq 8(%%r12), %%r12
+        \\ jmpq *(%%r12)
+    );
+}
+
+/// (addr)
+pub fn opReturn() callconv(.Naked) noreturn {
+    asm volatile (
+        \\ movq (%%r13), %%r12
+        \\ addq $0x08, %%r13
+        \\ jmpq *(%%r12)
+    );
+}
+
+// todo: Allow passing initial stack via array of words.
+// todo: Ensure correctness.
+// todo: Use remaining stack as return.
+// todo: Make it .C callconv and extern.
+// todo: Permute by calling conventions.
+pub fn execute(binary: []const Word, entry_addr: usize) void {
+    // https://wiki.osdev.org/System_V_ABI
+    @setCold(true);
+
+    var return_stack: [tolmac.RecursionLimit + 1]Word = undefined;
+
+    jumpstartSysV(&binary[entry_addr], &return_stack[return_stack.len - 2]);
+}
+
+const jumpstartSysV = @as(*const fn (thread: *const Word, return_stack: *Word) callconv(.SysV) void, @ptrCast(&jumpstartNakedSysV));
+
+// todo: Make sure to save every non-volatile register and restore it.
+// todo: Should we make frames well formed for walking?
+fn jumpstartNakedSysV() callconv(.Naked) void {
+    asm volatile (
+        \\ pushq %%rbp
+        \\ pushq %%r12
+        \\ pushq %%r13
+        \\
+        \\ movq %%rdi, %%r12
+        \\ movq %%rsi, %%r13
+        \\
+        \\ # Such device is used so that opReturn could be used for return.
+        \\     movq $0f, 8(%%r13)
+        \\     leaq 8(%%r13), %%rax
+        \\     movq %%rax, (%%r13)
+        \\     jmpq *(%%r12)
+        \\ 0:
+        \\
+        \\ popq %%r12
+        \\ popq %%r13
+        \\ popq %%rbp
+        \\ ret
+    );
+}

src/arch/x86-64/zov/ve-sistema.zig

@@ -0,0 +1,282 @@
+//! .zov.ve-sistema:x86-64
+//!
+//! Provides entry opcodes for System V calling convention, optimized for specific prototypes.
+//!
+
+// https://refspecs.linuxbase.org/elf/x86_64-abi-0.99.pdf
+
+// todo: Provide opcode that would dynamically dispatch based on marshaled C prototypes,
+//       which will be sufficient for rare prototypes sporadically used, so to not bloat
+//       the binary with all possible permutations or ask for them on comptime, which is unreasonable.
+
+const std = @import("std");
+const tolmac = @import("../../../tolmac.zig");
+
+/// Used for stack parameter passing.
+pub const WordLimit = 128;
+const AsmBufferLimit = 4096;
+const ClassBufferLimit = 256;
+
+const Class = enum {
+    void, // Denotes empty types.
+    integer,
+    sse,
+    sseup,
+    x87,
+    x87up,
+    no_class,
+    memory,
+};
+
+fn determiteClass(comptime T: type, buffer: []Class) []Class {
+    switch (@typeInfo(T)) {
+        .Void => &[1]Class{.void},
+        .Int => |int| {
+            switch (int.bits) {
+                0 => buffer[0] = .void,
+                1...64 => buffer[0] = .integer,
+                65...128 => @compileError("unimplemented"),
+                else => @compileError("invalid sysv parameter"),
+            }
+        },
+        .Float => |float| {
+            switch (float.bits) {
+                0 => buffer[0] = .void,
+                1...64 => buffer[0] = .sse,
+                65...80 => @compileError("unimplemented"),
+                81...128 => @compileError("unimplemented"),
+                else => @compileError("invalid sysv parameter"),
+            }
+        },
+        .Bool => buffer[0] = .integer,
+        .Pointer => |ptr| {
+            switch (ptr.size) {
+                .Slice => @compileError("invalid sysv parameter"),
+                else => buffer[0] = .integer,
+            }
+        },
+        .Fn => buffer[0] = .integer,
+        else => @compileError("unimplemented"),
+    }
+
+    return buffer[0 .. (@sizeOf(T) - 1) / 8 + 1];
+}
+
+// todo: Make sure duplicates are not made.
+// todo: Cache results for identical in effect devices.
+//
+/// (iw | -- (arbitrary amount of words))
+pub fn generateOpZovSysvFromPrototype(prototype: anytype) !*const fn () callconv(.Naked) noreturn {
+    // todo: Should we care about this?
+    // > The direction flag DF in the %rFLAGS register must be clear (set to “forward”
+    // > direction) on function entry and return.
+
+    // todo: Is our bool convention compatible?
+    // > Booleans, when stored in a memory object, are stored as single byte objects the
+    // > value of which is always 0 (false) or 1 (true). When stored in integer registers
+    // > (except for passing as arguments), all 8 bytes of the register are significant; any
+    // > nonzero value is considered true.
+
+    comptime {
+        const func = @typeInfo(@TypeOf(prototype)).Fn;
+
+        if (func.calling_convention != .SysV)
+            @compileError("Non SysV function passed");
+
+        var source_buffer = [_]u8{0} ** AsmBufferLimit;
+        var source_needle: usize = 0;
+
+        // idea: Try using REP for big consequent memory pushes.
+
+        // todo: In-stack returns by pointing %rdi directly to final destination.
+
+        // todo: Handle cases with more than 32 eightbytes on stack.
+        //       For that we would need to increment %rbp by 256 every once in a while,
+        //       either by storing its copy in volatile register or subtracting back after copy it done.
+
+        // todo: Test whether aligning by shifting is better.
+        const Prelude =
+            \\ movq %%rsp, %%rbp # Move stack pointer in non-volatile %rbp to restore later
+            \\ andq $-16, %%rsp # Align stack so that %rsp + 8 in callee is 16 aligned.
+            \\ subq $0x{x}, %%rsp
+            \\
+        ;
+
+        const Call =
+            \\ call *8(%%r12)
+            \\
+        ;
+
+        const Epilogue =
+            \\ movq %%rbp, %%rsp # Restore stack pointer
+            \\ addq $0x10, %%r12
+            \\ jmpq *(%%r12)
+            \\
+        ;
+
+        var integer_allocation: usize = 0;
+        const IntegerAllocations = [_][]const u8{ "rdi", "rsi", "rdx", "rcx", "r8", "r9" };
+        //  var sse_allocation: enum { xmm0, xmm1, xmm2, xmm3, xmm4, xmm5, xmm6, xmm7 } = .xmm0;
+
+        var class_buffer = [_]Class{.void} ** ClassBufferLimit;
+
+        // Calculate stack space used by parameters.
+        var parameter_stack_size: usize = 0;
+        for (func.params) |param| {
+            const classes = determiteClass(param.type.?, &class_buffer);
+            parameter_stack_size += 8 * classes.len;
+        }
+
+        source_needle += (try std.fmt.bufPrint(
+            source_buffer[source_needle..],
+            Prelude[0..],
+            .{if (parameter_stack_size % 16 == 0) 16 else 8},
+        )).len;
+
+        // Push parameters to appropriate registers and stack positions.
+        var stack_offset: usize = parameter_stack_size;
+        for (func.params) |param| {
+            const classes = determiteClass(param.type.?, &class_buffer);
+            for (classes) |class| {
+                stack_offset -= 8;
+                switch (class) {
+                    .integer => {
+                        if (integer_allocation < IntegerAllocations.len - 1) {
+                            source_needle += (try std.fmt.bufPrint(
+                                source_buffer[source_needle..],
+                                "movq {}(%%rbp), %%{s}\n",
+                                .{ stack_offset, IntegerAllocations[integer_allocation] },
+                            )).len;
+                            integer_allocation += 1;
+                        } else {
+                            source_needle += (try std.fmt.bufPrint(
+                                source_buffer[source_needle..],
+                                "pushq {}(%%rbp)\n",
+                                .{stack_offset},
+                            )).len;
+                        }
+                    },
+                    .void => {},
+                    else => @compileError("unimplemented"),
+                }
+            }
+        }
+
+        @memcpy(source_buffer[source_needle .. source_needle + Call.len], Call[0..]);
+        source_needle += Call.len;
+
+        @memcpy(source_buffer[source_needle .. source_needle + Epilogue.len], Epilogue[0..]);
+        source_needle += Epilogue.len;
+
+        return &struct {
+            fn op() callconv(.Naked) noreturn {
+                asm volatile (source_buffer[0..source_needle]);
+            }
+        }.op;
+    }
+}
+
+fn addInt1(a: u64) callconv(.SysV) void {
+    @setAlignStack(16);
+    if (a != 1)
+        @panic("addInt1");
+}
+
+fn addInt2(a: u64, b: u8) callconv(.SysV) void {
+    @setAlignStack(16);
+    if ((a + b) != 3)
+        @panic("addInt2");
+}
+
+fn addInt3(a: u64, b: u32, c: u16) callconv(.SysV) void {
+    @setAlignStack(16);
+    if ((a + b + c) != 6)
+        @panic("addInt3");
+}
+
+fn addInt4(a: u64, b: u32, c: u16, d: u8) callconv(.SysV) void {
+    @setAlignStack(16);
+    if ((a + b + c + d) != 10)
+        @panic("addInt4");
+}
+
+fn addInt5(a: u64, b: u32, c: u16, d: u8, e: u64) callconv(.SysV) void {
+    @setAlignStack(16);
+    if ((a + b + c + d + e) != 11)
+        @panic("addInt5");
+}
+
+fn addInt6(a: u64, b: u32, c: u16, d: u8, e: u64, f: i32) callconv(.SysV) void {
+    @setAlignStack(16);
+    if ((a + b + c + d + e + @as(u64, @intCast(f))) != 15)
+        @panic("addInt6");
+}
+
+fn addInt7(a: u64, b: u32, c: u16, d: u8, e: u64, f: i32, sa: u32) callconv(.SysV) void {
+    @setAlignStack(16);
+    if ((a + b + c + d + e + @as(u64, @intCast(f)) + sa) != 30)
+        @panic("addInt7");
+}
+
+fn addInt8(a: u64, b: u32, c: u16, d: u8, e: u64, f: i32, sa: u32, sb: u8) callconv(.SysV) void {
+    @setAlignStack(16);
+    if ((a + b + c + d + e + @as(u64, @intCast(f)) + sa + sb) != 40)
+        @panic("addInt8");
+}
+
+const opZov1Int = generateOpZovSysvFromPrototype(addInt1) catch unreachable;
+const opZov2Ints = generateOpZovSysvFromPrototype(addInt2) catch unreachable;
+const opZov3Ints = generateOpZovSysvFromPrototype(addInt3) catch unreachable;
+const opZov4Ints = generateOpZovSysvFromPrototype(addInt4) catch unreachable;
+const opZov5Ints = generateOpZovSysvFromPrototype(addInt5) catch unreachable;
+const opZov6Ints = generateOpZovSysvFromPrototype(addInt6) catch unreachable;
+const opZov7Ints = generateOpZovSysvFromPrototype(addInt7) catch unreachable;
+const opZov8Ints = generateOpZovSysvFromPrototype(addInt8) catch unreachable;
+
+test "integer parameter passing" {
+    const code = [_]tolmac.Word{
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        1,
+        @as(tolmac.Word, @intFromPtr(opZov1Int)),
+        @as(tolmac.Word, @intFromPtr(&addInt1)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        2,
+        @as(tolmac.Word, @intFromPtr(opZov2Ints)),
+        @as(tolmac.Word, @intFromPtr(&addInt2)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        3,
+        @as(tolmac.Word, @intFromPtr(opZov3Ints)),
+        @as(tolmac.Word, @intFromPtr(&addInt3)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        4,
+        @as(tolmac.Word, @intFromPtr(opZov4Ints)),
+        @as(tolmac.Word, @intFromPtr(&addInt4)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        1,
+        @as(tolmac.Word, @intFromPtr(opZov5Ints)),
+        @as(tolmac.Word, @intFromPtr(&addInt5)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        4,
+        @as(tolmac.Word, @intFromPtr(opZov6Ints)),
+        @as(tolmac.Word, @intFromPtr(&addInt6)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        15,
+        @as(tolmac.Word, @intFromPtr(opZov7Ints)),
+        @as(tolmac.Word, @intFromPtr(&addInt7)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        10,
+        @as(tolmac.Word, @intFromPtr(opZov8Ints)),
+        @as(tolmac.Word, @intFromPtr(&addInt8)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opReturn)),
+    };
+
+    tolmac.execute(&code, 0);
+}

src/main.zig

@@ -1,23 +0,0 @@
-const int = @import("interpreter.zig");
-
-pub fn main() !void {
-    // todo: Mixing return addresses in stack poses a challenge, hm.
-    const add = [_]int.Word{
-        @as(int.Word, @intFromPtr(&int.opSumWordsWithOverflow)),
-        @as(int.Word, @intFromPtr(&int.opReturn)),
-    };
-
-    const entry = [_]int.Word{
-        @as(int.Word, @intFromPtr(&int.opPushWord)),
-        1,
-        @as(int.Word, @intFromPtr(&int.opPushWord)),
-        2,
-        @as(int.Word, @intFromPtr(&int.opCall)),
-        @as(int.Word, @intFromPtr(&add)),
-        @as(int.Word, @intFromPtr(&int.opSinkWord)),
-        @as(int.Word, @intFromPtr(&int.opSinkWord)),
-        @as(int.Word, @intFromPtr(&int.opReturn)),
-    };
-
-    int.execute(&entry, 0);
-}

src/nmvm.zig

@@ -0,0 +1 @@
+pub const tolmac = @import("tolmac.zig");

src/platform/cosmopolitan/main.zig

@@ -0,0 +1,61 @@
+const tolmac = @import("nmvm").tolmac;
+const cosmo = @import("cosmopolitan.zig");
+
+fn printInt3(int: u64, other: u32, another: u16) callconv(.SysV) void {
+    @setAlignStack(16);
+    _ = cosmo.printf("%u\n", @as(c_uint, @intCast(int + other + another)));
+}
+
+fn printInt2(int: u64, other: u8) callconv(.SysV) void {
+    @setAlignStack(16);
+    _ = cosmo.printf("%u\n", @as(c_uint, @intCast(int + other)));
+}
+
+const opPrintInt3Zov = tolmac.generateOpZovSysvFromPrototype(printInt3) catch unreachable;
+const opPrintInt2Zov = tolmac.generateOpZovSysvFromPrototype(printInt2) catch unreachable;
+
+comptime {
+    @export(cosmopolitanMain, .{ .name = "main" });
+}
+
+// todo: No cosmopolitan main.
+
+fn cosmopolitanMain(argc: c_int, argv: [*][*:0]u8) callconv(.SysV) c_int {
+    _ = argc;
+    _ = argv;
+
+    const add = [_]tolmac.Word{
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSumWordsWithOverflow)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opReturn)),
+    };
+
+    const entry = [_]tolmac.Word{
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        1,
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        2,
+        @as(tolmac.Word, @intFromPtr(&tolmac.opCall)),
+        @as(tolmac.Word, @intFromPtr(&add)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        10,
+        @as(tolmac.Word, @intFromPtr(&tolmac.opPushWord)),
+        20,
+        @as(tolmac.Word, @intFromPtr(opPrintInt3Zov)),
+        @as(tolmac.Word, @intFromPtr(&printInt3)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(opPrintInt2Zov)),
+        @as(tolmac.Word, @intFromPtr(&printInt2)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opSinkWord)),
+        @as(tolmac.Word, @intFromPtr(&tolmac.opReturn)),
+    };
+
+    tolmac.execute(&entry, 0);
+
+    return 0;
+}
+
+test {
+    _ = @import("nmvm").tolmac;
+}

src/tolmac.zig

@@ -14,4 +14,7 @@
 // idea: 'JIT' could be done by simple op* compiled binary copying up until `jmpq *(%%rdi)`,
 //       with immediate operand prelude modified, which could be done procedurally.
 
+pub const Word = u64;
+pub const RecursionLimit = 1024;
+
 pub usingnamespace @import("arch/x86-64.zig");