fix(sdk): pce headers bypass

Author: kassane

build.zig

@@ -133,6 +133,10 @@ pub fn build(b: *std.Build) void {
     const atari8_target = b.resolveTargetQuery(.{ .cpu_arch = .mos, .os_tag = .atari8 });
     const atari8_gtia_mod = atari8GtiaHeaderMod(b, sdk_dep, atari8_target, optimize);
 
+    // Translated PCE headers for PC Engine.
+    const pce_target = b.resolveTargetQuery(.{ .cpu_arch = .mos, .os_tag = .pce });
+    const pce_mod = pceHeaderMod(b, sdk_dep, pce_target, optimize);
+
     // Host tool: converts MOS ELF symbol tables to Mesen label files (.mlb).
     const elf2mlb = b.addExecutable(.{
         .name = "elf2mlb",
@@ -564,6 +568,7 @@ pub fn build(b: *std.Build) void {
     {
         const step = b.step("pce-color-cycle", "Build PC Engine color-cycle example");
         const exe = addPceExe(b, sdk_dep, sdk_src, sdk_libs.pce orelse @panic("pce libs not built"), optimize, "pce-color-cycle", "pce/color-cycle/color-cycle.zig");
+        exe.root_module.addImport("pce", pce_mod);
         const install = b.addInstallArtifact(exe, .{ .dest_sub_path = "pce-color-cycle.pce" });
         step.dependOn(&install.step);
         b.getInstallStep().dependOn(&install.step);
@@ -574,6 +579,7 @@ pub fn build(b: *std.Build) void {
     {
         const step = b.step("pce-color-cycle-banked", "Build PC Engine banked color-cycle example");
         const exe = addPceExe(b, sdk_dep, sdk_src, sdk_libs.pce orelse @panic("pce libs not built"), optimize, "pce-color-cycle-banked", "pce/color-cycle-banked/color-cycle-banked.zig");
+        exe.root_module.addImport("pce", pce_mod);
         const install = b.addInstallArtifact(exe, .{ .dest_sub_path = "pce-color-cycle-banked.pce" });
         step.dependOn(&install.step);
         b.getInstallStep().dependOn(&install.step);
@@ -836,6 +842,24 @@ pub fn build(b: *std.Build) void {
     }
 }
 
+fn pceHeaderMod(
+    b: *std.Build,
+    sdk_dep: *std.Build.Dependency,
+    target: std.Build.ResolvedTarget,
+    opt: std.builtin.OptimizeMode,
+) *std.Build.Module {
+    const tc = b.addTranslateC(.{
+        .root_source_file = b.path("pce/pce.h"),
+        .target = target,
+        .optimize = opt,
+        .link_libc = false,
+    });
+    tc.addIncludePath(sdk_dep.path("mos-platform/pce-common/libpce/include"));
+    tc.addIncludePath(sdk_dep.path("mos-platform/pce-common"));
+    tc.addIncludePath(sdk_dep.path("mos-platform/common/include"));
+    return tc.createModule();
+}
+
 fn atari2600HeaderMod(
     b: *std.Build,
     sdk_dep: *std.Build.Dependency,
@@ -1643,6 +1667,11 @@ fn addPceExe(
     });
     exe.bundle_compiler_rt = false;
     exe.lto = .full;
+    // LTO DCE eliminates mosCallMainSection (in .call_main) because the
+    // linker KEEP() reference runs after LTO. Force both symbols to keep
+    // the .call_main JSR and the main() function itself.
+    exe.forceUndefinedSymbol("__zig_call_main_section");
+    exe.forceUndefinedSymbol("main");
     exe.root_module.addCSourceFile(.{
         .file = sdk_dep.path("mos-platform/pce/crt0/crt0.S"),
     });
@@ -1653,6 +1682,7 @@ fn addPceExe(
     exe.root_module.linkLibrary(libs.crt);
     exe.root_module.linkLibrary(libs.crt0);
     exe.root_module.linkLibrary(libs.c);
+    if (libs.crt0_obj) |obj| exe.root_module.addObject(obj);
     exe.setLinkerScript(wrapper_ld);
     exe.root_module.addImport("mos_panic", b.createModule(.{
         .root_source_file = b.path("sdk/panic.zig"),

pce/color-cycle-banked/color-cycle-banked.zig

@@ -1,19 +1,15 @@
 // Copyright (c) 2024 Matheus C. França
 // SPDX-License-Identifier: Apache-2.0
-//! PC Engine banked color-cycle demo.
-//! Declares ROM bank 1 at virtual offset 6 (0xC000), places cycle_color
-//! in that bank section, maps the bank at startup, then loops.
+//! PC Engine banked color-cycle demo — cycleColor() lives in ROM bank 1.
 pub const panic = @import("mos_panic");
+const pce = @import("pce");
 
-// translate-c cannot handle the volatile pointer cast macros in hardware.h
-// (they use C volatile casts that translate-c rejects), so we define the
-// VCE registers directly — same addresses as hardware.h.
+// IO_VCE_COLOR_INDEX / IO_VCE_COLOR_DATA: hardware.h volatile pointer-cast macros
+// are not emitted by translate-c (Aro drops them); keep @ptrFromInt directly.
 const IO_VCE_COLOR_INDEX: *volatile u16 = @ptrFromInt(0x0402);
 const IO_VCE_COLOR_DATA: *volatile u16 = @ptrFromInt(0x0404);
 
-var color: u16 = 0;
-
-// Emit the linker symbols that declare bank 1 at ROM offset 6 (8 KB unit).
+// Declare physical bank 1 at ROM offset 6 (0xC000).  Mirrors PCE_ROM_BANK_AT(1, 6).
 comptime {
     asm (
         \\.global __rom_bank1
@@ -24,31 +20,27 @@ comptime {
 }
 
 // Map ROM bank 1 to virtual address window 6 (0xC000).
-// Mirrors pce_rom_bank1_map() from pce/config.h: lda #bank_num; tam #(1<<6).
+// Mirrors pce_rom_bank1_map(): lda #bank_num; tam #(1<<6).
 fn pceRomBank1Map() void {
     asm volatile (
         \\lda #__rom_bank1_bank
         \\tam #64
     );
 }
 
-// Must be noinline and in .rom_bank1 section so the linker places it in bank 1.
+var color: u16 = 0;
+
+// Placed in ROM bank 1 so it runs from the banked window.
 noinline fn cycleColor() linksection(".rom_bank1") void {
     IO_VCE_COLOR_INDEX.* = 0x100;
     IO_VCE_COLOR_DATA.* = color;
     color +%= 1;
 }
 
 export fn main() void {
+    pce.pce_vdc_set_resolution(256, 240, 0);
     pceRomBank1Map();
     while (true) {
         cycleColor();
     }
 }
-
-// Required interrupt handler stubs for PCE vector table.
-export fn irq_vdc() callconv(.c) void {}
-export fn irq_timer() callconv(.c) void {}
-export fn nmi() callconv(.c) void {}
-export fn irq_ext() callconv(.c) void {}
-export fn irq_vdc_2() callconv(.c) void {}

pce/color-cycle/color-cycle.zig

@@ -1,25 +1,59 @@
 // Copyright (c) 2024 Matheus C. França
 // SPDX-License-Identifier: Apache-2.0
-//! PC Engine color-cycle demo.
-//! Writes a cycling 9-bit color to VCE palette entry 0 (background color).
-//! VCE registers: COLOR_INDEX at 0x0400, COLOR_DATA at 0x0402.
+//! PC Engine color-cycle demo — VCE entry 0x100 (backdrop) cycles through 9-bit colors.
 pub const panic = @import("mos_panic");
+const pce = @import("pce");
 
+// IO_VCE_COLOR_INDEX / IO_VCE_COLOR_DATA: hardware.h volatile pointer-cast macros
+// are not emitted by translate-c (Aro drops them); keep @ptrFromInt directly.
 const IO_VCE_COLOR_INDEX: *volatile u16 = @ptrFromInt(0x0402);
 const IO_VCE_COLOR_DATA: *volatile u16 = @ptrFromInt(0x0404);
+const IRQ_VDC: u8 = 0x02;
+
+// ticks and irq_vdc are defined together in module-level asm so that the asm
+// reference "inc ticks" is resolved by the assembler/linker rather than the
+// LTO optimizer (which treats inline-asm symbol names as opaque text and
+// cannot match them to LLVM IR globals).
+extern var ticks: u16;
+comptime {
+    asm (
+        \\.section .bss
+        \\.global ticks
+        \\ticks:
+        \\  .space 2
+        \\
+        \\.section .text
+        \\.global irq_vdc
+        \\irq_vdc:
+        \\  pha
+        \\  txa
+        \\  pha
+        \\  tya
+        \\  pha
+        \\  lda mos16($0000)
+        \\  and #0x20
+        \\  beq .Lskip_ticks
+        \\  inc ticks
+        \\  bne .Lskip_ticks
+        \\  inc ticks+1
+        \\.Lskip_ticks:
+        \\  pla
+        \\  tay
+        \\  pla
+        \\  tax
+        \\  pla
+        \\  rti
+    );
+}
 
 export fn main() void {
-    var color: u16 = 0;
+    pce.pce_vdc_set_resolution(256, 240, 0);
+    pce.pce_vdc_irq_vblank_enable();
+    pce.pce_irq_enable(IRQ_VDC);
+    asm volatile ("cli"); // enable CPU IRQs (pce_cpu_irq_enable inline asm not translated)
+    const tp: *volatile u16 = &ticks;
     while (true) {
-        IO_VCE_COLOR_INDEX.* = 0;
-        IO_VCE_COLOR_DATA.* = color & 0x1FF;
-        color +%= 1;
+        IO_VCE_COLOR_INDEX.* = 0x100;
+        IO_VCE_COLOR_DATA.* = tp.* >> 3;
     }
 }
-
-// Required interrupt handler stubs for PCE vector table (crt0.S declares them weak).
-export fn irq_vdc() callconv(.c) void {}
-export fn irq_timer() callconv(.c) void {}
-export fn nmi() callconv(.c) void {}
-export fn irq_ext() callconv(.c) void {}
-export fn irq_vdc_2() callconv(.c) void {}

pce/pce.h

@@ -0,0 +1,13 @@
+// Copyright (c) 2024 Matheus C. França
+// SPDX-License-Identifier: Apache-2.0
+// Minimal PCE libpce wrapper for translate-c.
+// Excludes bank.h (inline asm bank-switch stubs) and system.h (inline asm
+// pce_cpu_irq_enable/disable) — Aro cannot lower inline asm function bodies.
+// pce_irq_enable is declared here directly; its C signature translates cleanly.
+// hardware.h volatile pointer-cast macros (#define IO_VCE_COLOR_INDEX ...) are
+// silently dropped by Aro — use @ptrFromInt() in Zig source for MMIO registers.
+#include <stdint.h>
+#include <stdbool.h>
+#include <pce/vce.h>
+#include <pce/vdc.h>
+void pce_irq_enable(uint8_t mask);

sdk/build.zig

@@ -811,8 +811,24 @@ fn buildPce(
 ) Libs {
     const libpce_src = b.fmt("{s}/libpce/src", .{pce_common_dir});
     const libpce_inc = b.fmt("{s}/libpce/include", .{pce_common_dir});
+    // common/crt0/crt0.S provides .call_main (jsr main) and .fini_rts sections.
+    // Must be a TRUE object (not archive member): section-only contributions with no
+    // exported symbol are silently skipped by ld.lld archive extraction.
+    // Mirrors cmake add_platform_object_file(common-crt0-o).
+    const crt0_obj = b.addObject(.{
+        .name = "crt0",
+        .root_module = b.createModule(.{ .target = target, .optimize = opt }),
+    });
+    crt0_obj.root_module.addIncludePath(.{ .cwd_relative = com_asm });
+    crt0_obj.root_module.addIncludePath(.{ .cwd_relative = com_inc });
+    crt0_obj.root_module.addCSourceFiles(.{
+        .root = .{ .cwd_relative = crt0_dir },
+        .files = &.{"crt0.S"},
+    });
+    crt0_obj.lto = .none;
+
     // libcrt0: pce-specific crt0 files + common init-stack + exit-loop.
-    // Note: crt0/crt0.S is a standalone object added per-exe (not in this lib).
+    // Note: pce/crt0/crt0.S is a standalone object added per-exe (not in this lib).
     const libcrt0 = addLib(b, "crt0", target, opt);
     libcrt0.lto = .none;
     libcrt0.root_module.addIncludePath(.{ .cwd_relative = com_asm });
@@ -851,7 +867,7 @@ fn buildPce(
         },
     });
 
-    return .{ .crt = libcrt, .crt0 = libcrt0, .c = libc };
+    return .{ .crt = libcrt, .crt0 = libcrt0, .c = libc, .crt0_obj = crt0_obj };
 }
 
 fn buildAtari8CartStd(