From: Maxwell Beck <max@rastertail.net>
Date: Mon, 30 Dec 2024 23:44:29 +0000 (-0600)
Subject: Fix byte ready to CPU overflow flag sync
X-Git-Url: https://rastertail.net/scm/?a=commitdiff_plain;p=pico1541.git

Fix byte ready to CPU overflow flag sync
---

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0f4a923..fdff714 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,7 +5,7 @@ include(pico_sdk_import.cmake)
 project(pico1541 VERSION 0.1.0)
 pico_sdk_init()
 
-add_executable(pico1541 src/pico1541.c src/6502.c src/6522.c src/drive.c testbin/1541.o testbin/bsk1.o)
+add_executable(pico1541 src/pico1541.c src/6502.c src/6522.c src/drive.c testbin/1541.o testbin/memento_mori.o)
 pico_set_binary_type(pico1541 copy_to_ram)
 target_link_libraries(pico1541 pico_runtime pico_multicore hardware_timer)
 pico_add_extra_outputs(pico1541)
\ No newline at end of file
diff --git a/src/drive.c b/src/drive.c
index 64b765a..5bc2e3b 100644
--- a/src/drive.c
+++ b/src/drive.c
@@ -47,7 +47,7 @@ void drive_init(drive_t *drive) {
 	drive->current_idx = 0;
 	drive->lookahead_idx = 0;
 
-	drive_cycle(drive, 0, false);
+	drive_cycle(drive);
 }
 
 void drive_step_up(drive_t *drive) {
@@ -68,16 +68,19 @@ void drive_step_down(drive_t *drive) {
 	}
 }
 
-bool drive_cycle(drive_t *drive, uint8_t cycles, bool advance) {
+bool drive_advance(drive_t *drive, uint8_t cycles) {
 	bool byte_ready = false;
-	if (advance) {
-		for (uint8_t i = 0; i < cycles; i++) {
-			uint8_t j = (i + drive->current_idx) & (DRIVE_LOOKAHEAD - 1);
-			byte_ready |= drive->byte_ready[j];
-		}
-		drive->current_idx = (drive->current_idx + cycles) & (DRIVE_LOOKAHEAD - 1);
+
+	for (uint8_t i = 0; i < cycles; i++) {
+		uint8_t j = (i + drive->current_idx) & (DRIVE_LOOKAHEAD - 1);
+		byte_ready |= drive->byte_ready[j];
 	}
+	drive->current_idx = (drive->current_idx + cycles) & (DRIVE_LOOKAHEAD - 1);
 
+	return byte_ready;
+}
+
+void drive_cycle(drive_t *drive) {
 	while (drive->lookahead_idx != ((drive->current_idx - 1) & (DRIVE_LOOKAHEAD - 1))) {
 		uint8_t j = (drive->lookahead_idx + 1) & (DRIVE_LOOKAHEAD - 1);
 		uint8_t timer_next = drive->timer + BITRATE_PER_TRACK[drive->track];
@@ -194,6 +197,4 @@ bool drive_cycle(drive_t *drive, uint8_t cycles, bool advance) {
 		drive->lookahead_idx = j;
 		drive->timer = timer_next;
 	}
-
-	return byte_ready;
 }
diff --git a/src/drive.h b/src/drive.h
index e131c5c..aa72f60 100644
--- a/src/drive.h
+++ b/src/drive.h
@@ -42,6 +42,7 @@ typedef struct drive_s {
 void drive_init(drive_t *drive);
 void drive_step_up(drive_t *drive);
 void drive_step_down(drive_t *drive);
-bool drive_cycle(drive_t *drive, uint8_t cycles, bool advance);
+bool drive_advance(drive_t *drive, uint8_t cycles);
+void drive_cycle(drive_t *drive);
 
 #endif
\ No newline at end of file
diff --git a/src/pico1541.c b/src/pico1541.c
index 3489fee..fec76a3 100644
--- a/src/pico1541.c
+++ b/src/pico1541.c
@@ -18,7 +18,7 @@ const uint8_t DEVICE = 8;
 static uint8_t ram[2048];
 extern uint8_t _binary__Users_max_Documents_c64_roms_dos1541_start[16384];
 // extern uint8_t _binary__Users_max_Downloads_blackbird_1_2_Blackbird_1_2_d64_start[174848];
-extern uint8_t _binary__Users_max_Downloads_Bloodsuckers_StillRising_BSK_StillRising_disk1_d64_start[174848];
+extern uint8_t _binary__Users_max_Downloads_MementoMori_GP_MementoMori_GP_Disk1_d64_start[174848];
 
 uint32_t ts;
 cpu_t cpu;
@@ -138,14 +138,11 @@ void atn_irq_callback(uint pin, uint32_t flags) {
 
 void drive_thread() {
 	drive_init(&drive);
-	drive.image = _binary__Users_max_Downloads_Bloodsuckers_StillRising_BSK_StillRising_disk1_d64_start;
+	drive.image = _binary__Users_max_Downloads_MementoMori_GP_MementoMori_GP_Disk1_d64_start;
 	multicore_fifo_push_blocking(1);
 
-	while (true) {
-		uint32_t cycles = multicore_fifo_pop_blocking_inline();
-		if (drive_cycle(&drive, cycles, true) && (via2.pcr & 0b1110) == 0b1110) {
-			cpu.flags |= 1 << FLAG_V_BIT;
-		}
+	while (multicore_fifo_pop_blocking_inline()) {
+		drive_cycle(&drive);
 	}
 }
 
@@ -192,7 +189,10 @@ int main() {
 		}
 
 		uint8_t cycles = cpu_step(&cpu);
-		multicore_fifo_push_blocking_inline((uint32_t)cycles);
+		if (drive_advance(&drive, cycles) && (via2.pcr & 0b1110) == 0b1110) {
+			cpu.flags |= 1 << FLAG_V_BIT;
+		}
+		multicore_fifo_push_blocking_inline(1);
 
 		via_cycle(&via1, cycles);
 		via_cycle(&via2, cycles);