retarget_stdio.c

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/*
 * retarget_stdio.c
 *
 *  Created on: Jan 23, 2026
 *      Author: Souham Biswas
 *      GitHub: https://github.com/ironhide23586/icarus-os-core
 */
 
 
#include "icarus/kernel.h"
#include "icarus/scheduler.h"
 
#include "usbd_cdc_if.h"
#include "usbd_def.h"
#include "cmsis_gcc.h"
 
/* Function prototype */
int __io_putchar(int ch);
 
//int __io_putchar(int ch) {
//  enqueue_print_buffer(ch);
//  return ch;
//}
 
//
// Change your __io_putchar implementation
int __io_putchar(int ch) {
  /* Static variables must be in RAM_D1, not DTCM, for unprivileged access */
#ifndef HOST_TEST
  static uint8_t buf[64] __attribute__((section(".ram_d1")));
  static uint8_t i __attribute__((section(".ram_d1"))) = 0;
#else
  static uint8_t buf[64];
  static uint8_t i = 0;
#endif
 
  buf[i++] = (uint8_t)ch;
 
  // Flush on newline or when buffer is full
  {
    const uint8_t buf_size = (uint8_t)sizeof(buf);
    if ((ch == (int)'\n') || (i >= buf_size)) {
 
      uint8_t result = CDC_Transmit_FS(buf, i);
      uint16_t retry_count = 0u;
 
      while ((retry_count < 1000u) && (result == USBD_BUSY)) {
        result = CDC_Transmit_FS(buf, i);
        (void)task_blocking_sleep(1);
        retry_count++;
      }
      i = 0;
    }
  }
 
  return ch;
}