/* test_port.c -- the node's port: a write blocks the node until its
 * neighbour has served it (node.h; DECOMPOSITION.md section 6).
 *
 * At the level of opcodes: no word of the vocabulary is defined here.
 */
#include "v4/asm.h"
#include "v4/testcode.h"
#include <stdio.h>
#include <string.h>

static int failures = 0, checks = 0;
#define CHECK(c,...) do{checks++; if(!(c)){failures++; printf("FAIL %s:%d: ",__FILE__,__LINE__); printf(__VA_ARGS__); printf("\n");}}while(0)

/* The memory map is open (D-4); the test chooses the address. */
#define PORT ((v4_cell)(V4_NODE_WORDS - 16u))
#define MARK ((v4_cell)0x1234)
#define HOME ((v4_cell)8)                /* where a word returns to when the test called it */

static v4_node       n;
static v4_exec_state es;
static v4_heat       h;
static v4_asm        as;

#define O(name)  v4_asm_op(&as, V4_OP_##name)
#define LIT(v)   v4_asm_lit(&as, (v4_cell)(v))

static void start(v4_cell word)
{
    v4_dstack_reset(&n.ds);
    v4_rstack_reset(&n.rs);
    v4_exec_reset(&es);
    v4_heat_reset(&h);
    v4_rstack_push(&n.rs, HOME);
    n.p = word;
}

/* Run until the node is blocked, is back at HOME, or `max` words. */
static unsigned run(unsigned max)
{
    unsigned words = 0;
    while (words < max && !n.asking && n.p != HOME) { (void)v4_exec_step_word(&n, &es, &h); words++; }
    return words;
}

int main(void)
{
    v4_cell w_ask, w_mid, w_two;
    v4_uheat_t clock;

    printf("v4 port tests: V4_CELL_BITS=%d\n", V4_CELL_BITS);

    v4_asm_begin(&as, &n, 16);
    /* what KERNEL-WORD lays down: the request, the port, b! !b ; */
    w_ask = v4_asm_label(&as);
    LIT(7); LIT(PORT); O(BANG_B); O(STORE_B); O(SEMI);
    /* a write with more of the instruction word after it: dup + */
    w_mid = v4_asm_label(&as);
    LIT(5); LIT(PORT); O(BANG_B); O(STORE_B); O(DUP); O(ADD); O(SEMI);
    /* two writes one after the other */
    w_two = v4_asm_label(&as);
    LIT(PORT); O(BANG_B); LIT(1); O(STORE_B); LIT(2); O(STORE_B); O(SEMI);
    CHECK(v4_asm_ok(&as), "the test words assemble");

    /* ---- no port: the address is memory ---- */
    v4_node_reset(&n);
    v4_asm_begin(&as, &n, 16);
    w_ask = v4_asm_label(&as);
    LIT(7); LIT(PORT); O(BANG_B); O(STORE_B); O(SEMI);
    w_mid = v4_asm_label(&as);
    LIT(5); LIT(PORT); O(BANG_B); O(STORE_B); O(DUP); O(ADD); O(SEMI);
    w_two = v4_asm_label(&as);
    LIT(PORT); O(BANG_B); LIT(1); O(STORE_B); LIT(2); O(STORE_B); O(SEMI);
    CHECK(n.port == -1 && !n.asking, "a node has no port until one is attached");
    n.mem[PORT] = MARK;
    start(w_ask);
    (void)run(100);
    CHECK(n.p == HOME && !n.asking && n.mem[PORT] == 7, "with none, a store to the address writes memory and the word returns");

    /* ---- the write blocks ---- */
    v4_node_port_attach(&n, PORT);
    n.mem[PORT] = MARK;
    start(w_ask);
    v4_dstack_push(&n.ds, 11);
    v4_dstack_push(&n.ds, 22);
    (void)run(100);
    CHECK(n.asking && n.request == 7, "a store to the port blocks the node, with what it wrote: %ld", (long)n.request);
    CHECK(n.mem[PORT] == MARK, "and does not write memory");
    CHECK(n.p != HOME, "the word has not returned");
    CHECK(n.ds.depth == 2, "what was on the data stack is there for its neighbour");
    clock = es.anticlock;
    CHECK(v4_exec_step_word(&n, &es, &h) == 0 && v4_exec_step_word(&n, &es, &h) == 0, "a blocked node executes nothing");
    CHECK(es.anticlock == clock && n.asking, "however often it is stepped: the anti-clock does not move");

    /* the neighbour takes two values and leaves one, then says it is served */
    {
        v4_cell b = v4_dstack_pop(&n.ds), a = v4_dstack_pop(&n.ds);
        v4_dstack_push(&n.ds, a + b);
    }
    v4_node_port_served(&n);
    (void)run(100);
    CHECK(n.p == HOME && !n.asking, "served, the word goes on and returns");
    CHECK(n.ds.depth == 1 && v4_dstack_pop(&n.ds) == 33, "with what its neighbour left on the stack");

    /* ---- the rest of the instruction word waits ---- */
    start(w_mid);
    v4_dstack_push(&n.ds, 100);                       /* to be replaced while the node is blocked */
    (void)run(100);
    CHECK(n.asking && n.request == 5, "blocked in the middle of an instruction word");
    (void)v4_dstack_pop(&n.ds);
    v4_dstack_push(&n.ds, 21);                        /* the neighbour's result */
    v4_node_port_served(&n);
    (void)run(100);
    CHECK(n.p == HOME && n.ds.depth == 1 && v4_dstack_pop(&n.ds) == 42,
          "the opcodes after the store run when it is served, on what the neighbour left: dup + of 21");

    /* ---- one write after another ---- */
    start(w_two);
    (void)run(100);
    CHECK(n.asking && n.request == 1, "the first write blocks");
    v4_node_port_served(&n);
    (void)run(100);
    CHECK(n.asking && n.request == 2, "served, the node runs to the second and blocks again");
    v4_node_port_served(&n);
    (void)run(100);
    CHECK(n.p == HOME && !n.asking, "and returns when that is served");

    /* ---- a fault while blocked abandons the rest of the word ---- */
    start(w_mid);
    v4_dstack_push(&n.ds, 1);
    (void)run(100);
    CHECK(n.asking, "blocked again");
    v4_node_port_served(&n);
    v4_node_fault(&n, V4_FAULT_RAISED, 12);           /* no handler attached: the node stops */
    CHECK(v4_exec_step_word(&n, &es, &h) == 0 && n.stopped, "a node its neighbour faults does not go on with the word");

    /* ---- detaching ---- */
    v4_node_reset(&n);
    CHECK(n.port == -1 && !n.asking, "reset detaches the port");

    printf("  %d checks, %d failures\n", checks, failures);
    return failures != 0;
}