Add support for the parts of the KMod debug ports used by SGDK

2 files changed, 36 insertions, 1 deletions

diff --git a/vdp.c b/vdp.c
index b0e412f..81c7eec 100644
--- a/vdp.c
+++ b/vdp.c
@@ -10,6 +10,7 @@
 #include "render.h"
 #include "util.h"
 #include "event_log.h"
+#include "terminal.h"
 
 #define NTSC_INACTIVE_START 224
 #define PAL_INACTIVE_START 240
@@ -3782,6 +3783,33 @@ int vdp_control_port_write(vdp_context * context, uint16_t value)
 				if (reg == REG_MODE_1 || reg == REG_MODE_2 || reg == REG_MODE_4) {
 					update_video_params(context);
 				}
+			} else if (reg == REG_KMOD_CTRL) {
+				if (!(value & 0xFF)) {
+					context->system->enter_debugger = 1;
+				}
+			} else if (reg == REG_KMOD_MSG) {
+				char c = value;
+				if (c) {
+					context->kmod_buffer_length++;
+					if ((context->kmod_buffer_length + 1) > context->kmod_buffer_storage) {
+						context->kmod_buffer_storage = context->kmod_buffer_length ? 128 : context->kmod_buffer_length * 2;
+						context->kmod_msg_buffer = realloc(context->kmod_msg_buffer, context->kmod_buffer_storage);
+					}
+					context->kmod_msg_buffer[context->kmod_buffer_length - 1] = c;
+				} else if (context->kmod_buffer_length) {
+					context->kmod_msg_buffer[context->kmod_buffer_length] = 0;
+					init_terminal();
+					printf("KDEBUG MESSAGE: %s\n", context->kmod_msg_buffer);
+					context->kmod_buffer_length = 0;
+				}
+			} else if (reg == REG_KMOD_TIMER) {
+				if (!(value & 0x80)) {
+					init_terminal();
+					printf("KDEBUG TIMER: %d\n", (context->cycles - context->timer_start_cycle) / 7);
+				}
+				if (value & 0xC0) {
+					context->timer_start_cycle = context->cycles;
+				}
 			}
 		} else if (mode_5) {
 			context->flags |= FLAG_PENDING;
diff --git a/vdp.h b/vdp.h
index b58aca5..c33b42f 100644
--- a/vdp.h
+++ b/vdp.h
@@ -91,7 +91,10 @@ enum {
 	REG_DMALEN_H,
 	REG_DMASRC_L,
 	REG_DMASRC_M,
-	REG_DMASRC_H
+	REG_DMASRC_H,
+	REG_KMOD_CTRL=29,
+	REG_KMOD_MSG,
+	REG_KMOD_TIMER
 };
 
 //Mode reg 1
@@ -168,6 +171,10 @@ typedef struct {
 	uint32_t       *fb;
 	uint8_t        *done_composite;
 	uint32_t       *debug_fbs[VDP_NUM_DEBUG_TYPES];
+	char           *kmod_msg_buffer;
+	uint32_t       kmod_buffer_storage;
+	uint32_t       kmod_buffer_length;
+	uint32_t       timer_start_cycle;
 	uint32_t       output_pitch;
 	uint32_t       debug_fb_pitch[VDP_NUM_DEBUG_TYPES];
 	fifo_entry     fifo[FIFO_SIZE];