further changes for v1.7: cpu fixes, support for 'hardware' devices, display to vnc

[dcpu16] / hw_clock.c

diff --git a/hw_clock.c b/hw_clock.c
new file mode 100644 (file)
index 0000000..89d5912
--- /dev/null
+++ b/hw_clock.c
@@ -0,0 +1,112 @@
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "dcpu16.h"
+#include "hw_clock.h"
+
+static dcpu16_hw_signal_t clock_reset_;
+static dcpu16_hw_signal_t clock_cycle_;
+static dcpu16_hw_signal_t clock_hwi_;
+static struct dcpu16_hw hw_ = {
+    .name_  = "Generic Clock (compatible)",
+    .id_l   = 0xb402,
+    .id_h   = 0x12d0,
+    .ver    = 0x0001,
+    .mfg_l  = 0x0000,
+    .mfg_h  = 0x0000,
+    .hwi    = clock_hwi_,
+    .cycle  = clock_cycle_,
+    .reset  = clock_reset_,
+    .data   = (struct clock_ *)NULL
+};
+
+struct clock_ {
+    DCPU16_WORD cycle_;
+    DCPU16_WORD rate;
+    DCPU16_WORD tick;
+    DCPU16_WORD interrupt_message;
+};
+
+static
+void clock_reset_(struct dcpu16 *vm, void *data) {
+    struct clock_ *clock = (struct clock_ *)data;
+
+    (void)vm;
+
+    memset(clock, 0, sizeof *clock);
+}
+
+static
+void clock_cycle_(struct dcpu16 *vm, void *data) {
+    struct clock_ *clock = (struct clock_ *)data;
+
+    /* cycle is only called 100000 times per second */
+    /* maximum rate is 60hz / word_max = 3932160 */
+
+    if (clock->rate == 0)
+        return;
+
+    clock->cycle_++;
+    if (clock->cycle_ >= clock->rate) {
+        /* THIS CHECK IS WRONG, JUST A PLACEHOLDER */
+        clock->cycle_ = 0;
+        clock->tick += 1;
+
+        if (clock->interrupt_message) {
+            if (dcpu16_interrupt(vm, clock->interrupt_message))
+                vm->warn_cb_("%s: could not send interrupt", hw_.name_);
+        }
+    }
+}
+
+static
+void clock_hwi_(struct dcpu16 *vm, void *data) {
+    struct clock_ *clock = (struct clock_ *)data;
+    DCPU16_WORD reg_a = vm->reg[DCPU16_REG_A];
+    DCPU16_WORD reg_b = vm->reg[DCPU16_REG_B];
+
+    switch (reg_a) {
+        case 0: /* set tick gather rate, 60hz/B */
+            clock->rate = reg_b;
+            break;
+
+        case 1: /* fetch elapsed count since rate was set */
+            vm->reg[DCPU16_REG_C] = clock->tick;
+            break;
+
+        case 2:
+            clock->interrupt_message = reg_b;
+            break;
+    }
+}
+
+/* instantitate a new clock */
+struct dcpu16_hw *clock_new(struct dcpu16 *vm) {
+    struct dcpu16_hw *hw;
+
+    hw = calloc(1, sizeof *hw);
+    if (hw == NULL) {
+        vm->warn_cb_("%s():%s", "calloc", strerror(errno));
+        return NULL;
+    }
+    memcpy(hw, &hw_, sizeof *hw);
+    hw->data = calloc(1, sizeof hw->data);
+    if (hw->data == NULL) {
+        vm->warn_cb_("%s():%s", "calloc", strerror(errno));
+        free(hw);
+        return NULL;
+    }
+
+    return hw;
+}
+
+void clock_del(struct dcpu16_hw **hw) {
+    if (hw) {
+        free((*hw)->data);
+        (*hw)->data = NULL;
+
+        free((*hw));
+        *hw = NULL;
+    }
+}