From 88ee0e1befdb32f15419e9d50a512a79563acd28 Mon Sep 17 00:00:00 2001
From: Dennis Ranke <dennis.ranke@gmail.com>
Date: Sun, 2 Jan 2022 13:58:56 +0100
Subject: [PATCH] port rust tunnel example to zig

---
 examples/rust/build.sh   |   5 +++--
 examples/rust/readme.txt |  10 +++++-----
 examples/rust/tunnel.rs  |  15 ++++++++++-----
 examples/rust/tunnel.uw8 | Bin 119 -> 115 bytes
 examples/zig/.gitignore  |   2 ++
 examples/zig/build.zig   |  37 +++++++++++++++++++++++++++++++++++++
 examples/zig/main.zig    |  20 ++++++++++++++++++++
 7 files changed, 77 insertions(+), 12 deletions(-)
 create mode 100644 examples/zig/.gitignore
 create mode 100644 examples/zig/build.zig
 create mode 100644 examples/zig/main.zig

diff --git a/examples/rust/build.sh b/examples/rust/build.sh
index 0ecec33..b9893d2 100755
--- a/examples/rust/build.sh
+++ b/examples/rust/build.sh
@@ -1,3 +1,4 @@
-rustc --target=wasm32-unknown-unknown --crate-type cdylib -C opt-level="z" -C "link-args=--import-memory --initial-memory=262144 -zstack-size=65536" -o tunnel.wasm tunnel.rs && \
+rustc --target=wasm32-unknown-unknown --crate-type cdylib -C opt-level="z" -C "link-args=--import-memory --initial-memory=262144 -zstack-size=90000" -o tunnel.wasm tunnel.rs && \
 uw8 filter-exports tunnel.wasm tunnel.wasm && \
-wasm-opt -Oz -o tunnel.wasm tunnel.wasm
+wasm-opt -Oz --strip-producers -o tunnel.wasm tunnel.wasm && \
+uw8 pack -l 9 tunnel.wasm tunnel.uw8
diff --git a/examples/rust/readme.txt b/examples/rust/readme.txt
index 562782f..be2774d 100644
--- a/examples/rust/readme.txt
+++ b/examples/rust/readme.txt
@@ -5,14 +5,14 @@ A nightly rust compiler is needed for the unstable sqrtf32
 intrinsic.
 
 Simply compiling with rustc as shown in build.sh results in a
-371 byte tunnel.wasm. Using wasm-opt this can be reduced to
-260 bytes.
+361 byte tunnel.wasm. Using wasm-opt this can be reduced to
+255 bytes.
 
 When you disassemble this wasm file using wasm2wat you can see
 these globals and exports:
 
-(global (;0;) i32 (i32.const 65536))
-(global (;1;) i32 (i32.const 65536))
+(global (;0;) i32 (i32.const 90000))
+(global (;1;) i32 (i32.const 90000))
 (export "__data_end" (global 0))
 (export "__heap_base" (global 1))
 
@@ -23,5 +23,5 @@ referenced by the exports and we can remove them using
 'uw8 filter-exports' (preferably before running wasm-opt) which
 removes all exports except those used by the MicroW8 platform.
 
-This gives us a 216 byte wasm file. Running this through
+This gives us a 211 byte wasm file. Running this through
 uw8 pack brings us to the final size of 119 bytes.
\ No newline at end of file
diff --git a/examples/rust/tunnel.rs b/examples/rust/tunnel.rs
index 83527fe..5f62d92 100644
--- a/examples/rust/tunnel.rs
+++ b/examples/rust/tunnel.rs
@@ -38,16 +38,21 @@ fn ftoi(v: f32) -> i32 {
 
 #[no_mangle]
 pub fn upd() {
-    for i in 0..320 * 240 {
-        let t = time() * 63 as f32;
+    let mut i: i32 = 0;
+    loop {
+        let t = time() * 63.;
         let x = (i % 320 - 160) as f32;
         let y = (i / 320 - 120) as f32;
-        let d = 40000 as f32 / sqrt(x * x + y * y + 1 as f32);
-        let u = atan2(x, y) * 512f32 / 3.141;
-        let c = (ftoi(d + t * 2 as f32) ^ ftoi(u + t)) as u8 >> 4;
+        let d = 40000 as f32 / sqrt(x * x + y * y + 1.);
+        let u = atan2(x, y) * 512. / 3.141;
+        let c = (ftoi(d + t * 2.) ^ ftoi(u + t)) as u8 >> 4;
         unsafe {
             *((120 + i) as *mut u8) = c;
         }
+        i += 1;
+        if i >= 320*240 {
+            break;
+        }
     }
 }
 
diff --git a/examples/rust/tunnel.uw8 b/examples/rust/tunnel.uw8
index 50c01f3f3435ee5b6c8f43743f679c17cd100ffc..17ff4daa706a5c70b9740a79582df325e01dba36 100644
GIT binary patch
literal 115
zcmV-(0F3_v5Z8u|Z<y}KzwY%}@??@ow}X1GN|57}-z|Hw66uBj0^+3klJ`%X^v)fq
z3%}uYYu^`L4~%TGua<>|#{&AWW@?a<a7e7vpVsqqhK)H=%wJ7Dzlc-){pb?-_U{L{
V#T`4CJKwQB#fIADS#LJf0_~0YKr{dV

literal 119
zcmV--0Eqtr1#ia}{*%7ra>hbgU8bpqy|#X0LF+0s*nH{b>t`VtLE{d)%$6?ECNRU!
z^qaUOzNvK8)5AEzspQZ3njgWf=E#z09qo+t%?E+p%iI)|LBjg6m~*6PThd6Sn6$<x
ZY*wac<Sy$Ac<XdQT2s8M(xv@f<r#ctLk|D|

diff --git a/examples/zig/.gitignore b/examples/zig/.gitignore
new file mode 100644
index 0000000..7608bcb
--- /dev/null
+++ b/examples/zig/.gitignore
@@ -0,0 +1,2 @@
+/zig-cache/
+/zig-out/
\ No newline at end of file
diff --git a/examples/zig/build.zig b/examples/zig/build.zig
new file mode 100644
index 0000000..8deb34c
--- /dev/null
+++ b/examples/zig/build.zig
@@ -0,0 +1,37 @@
+const std = @import("std");
+
+pub fn build(b: *std.build.Builder) void {
+    const mode = std.builtin.Mode.ReleaseSmall;
+
+    const lib = b.addSharedLibrary("cart", "main.zig", .unversioned);
+    lib.setBuildMode(mode);
+    lib.setTarget(.{ .cpu_arch = .wasm32, .os_tag = .freestanding });
+    lib.import_memory = true;
+    lib.initial_memory = 262144;
+    lib.max_memory = 262144;
+    lib.global_base = 81920;
+    lib.stack_size = 8192;
+    lib.install();
+
+    if (lib.install_step) |install_step| {
+        const run_filter_exports = b.addSystemCommand(&[_][]const u8{
+            "uw8", "filter-exports", "zig-out/lib/cart.wasm", "zig-out/lib/cart-filtered.wasm"
+        });
+        run_filter_exports.step.dependOn(&install_step.step);
+
+        const run_wasm_opt = b.addSystemCommand(&[_][]const u8{
+            "wasm-opt", "-Oz", "-o", "zig-out/cart.wasm", "zig-out/lib/cart-filtered.wasm"
+        });
+        run_wasm_opt.step.dependOn(&run_filter_exports.step);
+
+        const run_uw8_pack = b.addSystemCommand(&[_][]const u8{
+            "uw8", "pack", "-l", "9", "zig-out/cart.wasm", "zig-out/cart.uw8"
+        });
+        run_uw8_pack.step.dependOn(&run_wasm_opt.step);
+
+        const make_opt = b.step("make_opt", "make size optimized cart");
+        make_opt.dependOn(&run_uw8_pack.step);
+
+        b.default_step = make_opt;
+    }
+}
diff --git a/examples/zig/main.zig b/examples/zig/main.zig
new file mode 100644
index 0000000..4e6524a
--- /dev/null
+++ b/examples/zig/main.zig
@@ -0,0 +1,20 @@
+extern fn atan2(x: f32, y: f32) f32;
+extern fn time() f32;
+
+pub const FRAMEBUFFER: *[320*240]u8 = @intToPtr(*[320*240]u8, 120);
+
+export fn upd() void {
+    var i: u32 = 0;
+    while(true) {
+        var t = time() * 63.0;
+        var x = @intToFloat(f32, (@intCast(i32, i % 320) - 160));
+        var y = @intToFloat(f32, (@intCast(i32, i / 320) - 120));
+        var d = 40000.0 / @sqrt(x * x + y * y + 1.0);
+        var u = atan2(x, y) * 512.0 / 3.141;
+        var c = @intCast(u8, (@floatToInt(i32, d + t * 2.0) ^ @floatToInt(i32, u + t)) & 255) >> 4;
+
+        FRAMEBUFFER[@as(usize, i)] = c;
+        i += 1;
+        if(i >= 320*240) { break; }
+    }
+}
\ No newline at end of file