VeniVidiVici
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nvboard
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nvboard: change the condition of calling uart->check_tx() 

* this can reduce the number of memory access
This commit is contained in:
Zihao Yu 2024-01-04 22:10:25 +08:00
parent aedd663a5e
commit 54fe35b910
3 changed files with 7 additions and 13 deletions
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1
include/uart.h
View File

@ -9,7 +9,6 @@ private:
Term *term;
int state;
uint16_t divisor;
uint16_t divisor_cnt;
uint8_t data;
bool need_update_gui;
uint8_t *p_tx;

5
src/nvboard.cpp
View File

@ -38,9 +38,8 @@ void nvboard_update() {
if (!is_kb_idle) kb->update_state();
extern UART* uart;
extern bool is_uart_idle;
extern uint8_t *uart_tx_ptr;
if (!(is_uart_idle && *uart_tx_ptr)) uart->check_tx();
extern int16_t uart_divisor_cnt;
if ((-- uart_divisor_cnt) < 0) uart->check_tx();
static uint64_t last = 0;
static int cpf = 1; // count per frame

14
src/uart.cpp
View File

@ -2,17 +2,16 @@
#include <uart.h>
UART* uart = NULL;
bool is_uart_idle = true;
uint8_t *uart_tx_ptr = NULL;
int16_t uart_divisor_cnt = 0;
UART::UART(SDL_Renderer *rend, int cnt, int init_val, int ct, int x, int y, int w, int h):
Component(rend, cnt, init_val, ct),
state(0), divisor(16), need_update_gui(false) {
term = new Term(rend, x, y, w, h);
divisor_cnt = divisor - 1;
uart_divisor_cnt = divisor - 1;
int len = pin_array[UART_TX].vector_len;
assert(len == 0 || len == 1); // either unbound or bound to 1 bit signal
uart_tx_ptr = (uint8_t *)pin_array[UART_TX].ptr;
p_tx = (uint8_t *)pin_array[UART_TX].ptr;
}
UART::~UART() {
@ -24,14 +23,12 @@ void UART::update_gui() {
}
void UART::check_tx() {
if (divisor_cnt > 0) { divisor_cnt --; return; }
divisor_cnt = divisor - 1;
uart_divisor_cnt = divisor - 1;
uint8_t tx = *uart_tx_ptr;
uint8_t tx = *p_tx;
if (state == 0) { // idle
if (!tx) { // start bit
data = 0;
is_uart_idle = false;
state ++;
}
} else if (state >= 1 && state <= 8) { // data
@ -41,7 +38,6 @@ void UART::check_tx() {
if (tx) {
term->feed_ch(data);
state = 0;
is_uart_idle = true;
need_update_gui = true;
} // stop bit
}