112 lines
4.2 KiB
Text
112 lines
4.2 KiB
Text
# emit_machine.ludic — `machine <state> { state Name = v { .. } }` dispatches on
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# an int state store; `become Name` writes the target state's value back. The
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# store is either a named program-scope `var` (loaded/stored directly) or, for
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# older code, a register index (reg()/set_reg()).
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# If `a` names a program-scope `var`, return it; else null (a register index).
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function machine_var(a: Node) -> Node {
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if a.kind == E_ID {
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let g = find_global(a.s)
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if (g != null) { if g.kind == N_VAR { return g } }
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}
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return null
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}
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# 0.S: a machine over a state's field (`machine hero.mode`) or a local: its address, else null
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var g_mach_ty: pointer = null
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function machine_addr(a: Node) -> pointer {
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if a.kind == E_MEMBER {
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let p = emit_member_addr(a)
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g_mach_ty = g_addr_ty
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return p
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}
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if a.kind == E_ID {
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let li = loc_find(a.s)
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if li >= 0 {
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g_mach_ty = loc_ty[li]
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return loc_reg[li]
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}
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let gv = machine_var(a)
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if gv != null {
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g_mach_ty = gv.ty
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return `@g_{a.s}`
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}
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}
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return null
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}
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# the value a state dispatches on: its explicit `= expr`; else, when the machine's
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# store is a `var` declared with an enum type, the variant named like the state
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# (`var mode: HeroState` + `state Rolling` -> HeroState.Rolling); else its ordinal.
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function machine_state_value(m: Node, state: Node) -> pointer {
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if (state.b != null) { return emit_expr(state.b).code }
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g_mach_ty = null
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let addr = machine_addr(m.a)
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let ty = g_mach_ty
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if addr != null and ty != null {
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let ord = enum_ordinal(ty, state.s)
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if ord >= 0 { return itoa(ord) }
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if (find_enum(ty) != null) { perr(`machine state {state.s} is not a variant of enum {ty}`) }
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}
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return itoa(state.ival)
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}
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function emit_machine(st: Node) -> void {
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let addr = machine_addr(st.a)
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var s: pointer = ""
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if (addr != null) { s = emit_bind(`load i32, ptr {addr}`) }
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else {
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let regv = emit_expr(st.a)
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s = emit_bind(`call i32 @fn_rt_reg(i32 {regv.code})`)
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}
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if nmach < len(mach_stk) { mach_stk[nmach] = st } else { push(mach_stk, st) }
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nmach += 1
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let endl = lbl("smend")
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var i = 0
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while i < len(st.kids) {
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let state = st.kids[i]
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let v = machine_state_value(st, state)
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let c = emit_bind(`icmp eq i32 {s}, {v}`)
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let body = lbl("sbody"); let nxt = lbl("sarm")
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emit(" br i1 "); emit(c); emit(", label %"); emit(body); emit(", label %"); emit(nxt); emit("\n")
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emit(body); emit(":\n"); g_term = false
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emit_block(state.a)
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if not g_term { emit(" br label %"); emit(endl); emit("\n") }
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emit(nxt); emit(":\n"); g_term = false
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i += 1
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}
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if not g_term { emit(" br label %"); emit(endl); emit("\n") }
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emit(endl); emit(":\n"); g_term = false
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nmach -= 1
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}
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# `become Name` — a machine state transition when Name is a state of an
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# enclosing `machine`, otherwise a scene transition. A scene transition runs the
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# source scene's on-exit, stores the target scene id into @L_scene, and runs the
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# target's on-enter (two direct calls and a store — no dispatch table).
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function emit_become(st: Node) -> void {
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if nmach > 0 { # inside a machine: try a state first
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let m = mach_stk[nmach - 1]
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var target: Node = null
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var i = 0
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while i < len(m.kids) { if (m.kids[i].s == st.s) { target = m.kids[i] }; i += 1 }
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if (target != null) {
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let sv = machine_state_value(m, target)
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let addr = machine_addr(m.a)
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if (addr != null) {
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emit(` store i32 {sv}, ptr {addr}\n`)
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} else {
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let regv = emit_expr(m.a)
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emit(" call void @fn_rt_set_reg(i32 "); emit(regv.code); emit(", i32 "); emit(sv); emit(")\n")
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}
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return
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}
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}
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let sc = find_scene(st.s) # else a scene transition
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if (sc == null) { perr(`become: no state or scene {st.s}`) }
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# leave the scene we are in: statically known inside a scene's own handler, else
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# (a global handler, an event listener, a function) whichever scene is live now
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if (g_cur_scene != null) { emit(" call void @scene_exit_"); emit(g_cur_scene.s); emit("()\n") }
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else { emit(" call void @L_scene_leave()\n") }
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emit(" store i32 "); emit(itoa(sc.ival)); emit(", ptr @L_scene\n")
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emit(" call void @scene_enter_"); emit(sc.s); emit("()\n")
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}
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