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- #include <Lib/USBLib.h>
- #include "usb_dev.h"
- #include "usb_mem.h"
-
- #define NUM_BUF 30
-
- __attribute__ ((section(".usbbuffers"), used))
- //static unsigned char usb_buffer_memory[NUM_BUF * sizeof(usb_packet_t)];
- unsigned char usb_buffer_memory[NUM_BUF * sizeof(usb_packet_t)];
-
- static uint32_t usb_buffer_available = 0xFFFFFFFF;
-
- // use bitmask and CLZ instruction to implement fast free list
- // http://www.archivum.info/gnu.gcc.help/2006-08/00148/Re-GCC-Inline-Assembly.html
- // http://gcc.gnu.org/ml/gcc/2012-06/msg00015.html
- // __builtin_clz()
-
- usb_packet_t * usb_malloc(void)
- {
- unsigned int n, avail;
- uint8_t *p;
-
- __disable_irq();
- avail = usb_buffer_available;
- n = __builtin_clz(avail); // clz = count leading zeros
- if (n >= NUM_BUF) {
- __enable_irq();
- return NULL;
- }
- //serial_print("malloc:");
- //serial_phex(n);
- //serial_print("\n");
-
- usb_buffer_available = avail & ~(0x80000000 >> n);
- __enable_irq();
- p = usb_buffer_memory + (n * sizeof(usb_packet_t));
- //serial_print("malloc:");
- //serial_phex32((int)p);
- //serial_print("\n");
- *(uint32_t *)p = 0;
- *(uint32_t *)(p + 4) = 0;
- return (usb_packet_t *)p;
- }
-
- // for the receive endpoints to request memory
- extern uint8_t usb_rx_memory_needed;
- extern void usb_rx_memory(usb_packet_t *packet);
-
- void usb_free(usb_packet_t *p)
- {
- unsigned int n, mask;
-
- //serial_print("free:");
- n = ((uint8_t *)p - usb_buffer_memory) / sizeof(usb_packet_t);
- if (n >= NUM_BUF) return;
- //serial_phex(n);
- //serial_print("\n");
-
- // if any endpoints are starving for memory to receive
- // packets, give this memory to them immediately!
- if (usb_rx_memory_needed && usb_configuration) {
- //serial_print("give to rx:");
- //serial_phex32((int)p);
- //serial_print("\n");
- usb_rx_memory(p);
- return;
- }
-
- mask = (0x80000000 >> n);
- __disable_irq();
- usb_buffer_available |= mask;
- __enable_irq();
-
- //serial_print("free:");
- //serial_phex32((int)p);
- //serial_print("\n");
- }
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