Defining the assembly construct.

• §1. Definition
• §2. Instructions
• §4. Creating from textual Inter syntax
• §5. Writing to textual Inter syntax
• §6. Access function

§1. Definition. For what this does and why it is used, see Textual Inter (in inter).

void AssemblyInstruction::define_construct?Usage of AssemblyInstruction::define_construct:
Inter Constructs - §15(void) {
    inter_construct *IC = InterInstruction::create_construct(ASSEMBLY_IST, I"assembly");
    InterInstruction::specify_syntax(IC, I"assembly TOKEN");
    InterInstruction::data_extent_always(IC, 1);
    InterInstruction::allow_in_depth_range(IC, 1, INFINITELY_DEEP);
    InterInstruction::permit(IC, INSIDE_CODE_PACKAGE_ICUP);
    METHOD_ADD(IC, CONSTRUCT_READ_MTID, AssemblyInstruction::read);
    METHOD_ADD(IC, CONSTRUCT_VERIFY_MTID, AssemblyInstruction::verify);
    METHOD_ADD(IC, CONSTRUCT_WRITE_MTID, AssemblyInstruction::write);
}

§2. Instructions. In bytecode, the frame of an assembly instruction is laid out with the compulsory words — see Inter Nodes — followed by:

define WHICH_ASSEMBLY_IFLD (DATA_IFLD + 0)

inter_error_message *AssemblyInstruction::new?Usage of AssemblyInstruction::new:
§4(inter_bookmark *IBM, inter_ti which,
    inter_ti level, inter_error_location *eloc) {
    inter_tree_node *P = Inode::new_with_1_data_field(IBM, ASSEMBLY_IST,
        /* WHICH_ASSEMBLY_IFLD: */ which,
        eloc, (inter_ti) level);
    inter_error_message *E = VerifyingInter::instruction(InterBookmark::package(IBM), P);
    if (E) return E;
    NodePlacement::move_to_moving_bookmark(P, IBM);
    return NULL;
}

§3. Verification consists only of sanity checks. Note that WHICH_ASSEMBLY_IFLD is required to be one of these:

enum ASM_ARROW_ASMMARKER from 1
enum ASM_SP_ASMMARKER
enum ASM_RTRUE_ASMMARKER
enum ASM_RFALSE_ASMMARKER
enum ASM_NEG_ASMMARKER
enum ASM_NEG_RTRUE_ASMMARKER
enum ASM_NEG_RFALSE_ASMMARKER

void AssemblyInstruction::verify?Usage of AssemblyInstruction::verify:
§1(inter_construct *IC, inter_tree_node *P,
    inter_package *owner, inter_error_message **E) {
    inter_ti which = P->W.instruction[WHICH_ASSEMBLY_IFLD];
    if ((which == 0) || (which > ASM_NEG_RFALSE_ASMMARKER)) {
        *E = Inode::error(P, I"bad assembly marker code", NULL);
        return;
    }
}

§4. Creating from textual Inter syntax.

void AssemblyInstruction::read?Usage of AssemblyInstruction::read:
§1(inter_construct *IC, inter_bookmark *IBM,
    inter_line_parse *ilp, inter_error_location *eloc, inter_error_message **E) {
    text_stream *marker_text = ilp->mr.exp[0];
    inter_ti which = 0;
         if (Str::eq(marker_text, I"store_to"))              which = ASM_ARROW_ASMMARKER;
    else if (Str::eq(marker_text, I"stack"))                 which = ASM_SP_ASMMARKER;
    else if (Str::eq(marker_text, I"return_true_if_true"))   which = ASM_RTRUE_ASMMARKER;
    else if (Str::eq(marker_text, I"return_false_if_true"))  which = ASM_RFALSE_ASMMARKER;
    else if (Str::eq(marker_text, I"branch_if_false"))       which = ASM_NEG_ASMMARKER;
    else if (Str::eq(marker_text, I"return_true_if_false"))  which = ASM_NEG_RTRUE_ASMMARKER;
    else if (Str::eq(marker_text, I"return_false_if_false")) which = ASM_NEG_RFALSE_ASMMARKER;
    else { *E = InterErrors::plain(I"unrecognised 'assembly' marker", eloc); return; }

    *E = AssemblyInstruction::new(IBM, which, (inter_ti) ilp->indent_level, eloc);
}

§5. Writing to textual Inter syntax.

void AssemblyInstruction::write?Usage of AssemblyInstruction::write:
§1(inter_construct *IC, OUTPUT_STREAM, inter_tree_node *P) {
    inter_ti which = AssemblyInstruction::which_marker(P);
    switch (which) {
        case ASM_ARROW_ASMMARKER:      WRITE("assembly store_to"); break;
        case ASM_SP_ASMMARKER:         WRITE("assembly stack"); break;
        case ASM_RTRUE_ASMMARKER:      WRITE("assembly return_true_if_true"); break;
        case ASM_RFALSE_ASMMARKER:     WRITE("assembly return_false_if_true"); break;
        case ASM_NEG_ASMMARKER:        WRITE("assembly branch_if_false"); break;
        case ASM_NEG_RTRUE_ASMMARKER:  WRITE("assembly return_true_if_false"); break;
        case ASM_NEG_RFALSE_ASMMARKER: WRITE("assembly return_false_if_false"); break;
    }
}

§6. Access function.

inter_ti AssemblyInstruction::which_marker?Usage of AssemblyInstruction::which_marker:
§5(inter_tree_node *P) {
    inter_ti which = P->W.instruction[WHICH_ASSEMBLY_IFLD];
    if ((which == 0) || (which > ASM_NEG_RFALSE_ASMMARKER))
        internal_error("bad assembly marker");
    return which;
}