From 735586f5f8858a550d3c2cf2c925a3c4e7d14f03 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sat, 19 Oct 2019 21:20:34 -0400
Subject: [PATCH] Corrects tabs; adds potential output_border optimisation.
---
Machines/AmstradCPC/AmstradCPC.cpp | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/Machines/AmstradCPC/AmstradCPC.cpp b/Machines/AmstradCPC/AmstradCPC.cpp
index c570b341a..ace3aaa52 100644
--- a/Machines/AmstradCPC/AmstradCPC.cpp
+++ b/Machines/AmstradCPC/AmstradCPC.cpp
@@ -222,9 +222,9 @@ class CRTCBusHandler {
if(cycles_) {
switch(previous_output_mode_) {
default:
- case OutputMode::Blank: crt_.output_blank(cycles_ * 16); break;
+ case OutputMode::Blank: crt_.output_blank(cycles_ * 16); break;
case OutputMode::Sync: crt_.output_sync(cycles_ * 16); break;
- case OutputMode::Border: output_border(cycles_); break;
+ case OutputMode::Border: output_border(cycles_); break;
case OutputMode::ColourBurst: crt_.output_default_colour_burst(cycles_ * 16); break;
case OutputMode::Pixels:
crt_.output_data(cycles_ * 16, size_t(cycles_ * 16 / pixel_divider_));
@@ -256,7 +256,8 @@ class CRTCBusHandler {
((state.refresh_address & 0x3000) << 2)
);
- // fetch two bytes and translate into pixels
+ // Fetch two bytes and translate into pixels. Guaranteed: the mode can change only at
+ // hsync, so there's no risk of pixel_pointer_ passing 320 without hitting 320.
switch(mode_) {
case 0:
reinterpret_cast<uint16_t *>(pixel_pointer_)[0] = mode0_output_[ram_[address]];
@@ -369,9 +370,14 @@ class CRTCBusHandler {
private:
void output_border(int length) {
- uint8_t *colour_pointer = static_cast<uint8_t *>(crt_.begin_data(1));
- if(colour_pointer) *colour_pointer = border_;
- crt_.output_level(length * 16);
+ assert(length >= 0);
+ if(border_) {
+ uint8_t *const colour_pointer = static_cast<uint8_t *>(crt_.begin_data(1));
+ if(colour_pointer) *colour_pointer = border_;
+ crt_.output_level(length * 16);
+ } else {
+ crt_.output_blank(length * 16);
+ }
}
#define Mode0Colour0(c) ((c & 0x80) >> 7) | ((c & 0x20) >> 3) | ((c & 0x08) >> 2) | ((c & 0x02) << 2)