; ***************************************************************************
; copyright   : (C) 2025 by Martin Preuss
; email       : martin@libchipcard.de
;
; ***************************************************************************
; * This file is part of the project "AqHome".                              *
; * Please see toplevel file COPYING of that project for license details.   *
; ***************************************************************************


; ===========================================================================
; defs




; ===========================================================================
; code segment

.cseg

; ---------------------------------------------------------------------------
; @routine NET_Buffer_Init @global
;
; @clobbers R16, R17, X

NET_Buffer_Init:
  ldi xl, LOW(netBuffers)
  ldi xh, HIGH(netBuffers)
  m_fixedbuf_init NET_BUFFERS_SIZE, NET_BUFFERS_NUM
  ret
; @end



; ---------------------------------------------------------------------------
; @routine NET_Buffer_Alloc @global
;
; @return CFLAG set if buffer available, cleared otherwise
; @return r16 buffer num
; @return X pointer to start of buffer
; @clobbers R16, R17, X

NET_Buffer_Alloc:
  ldi xl, LOW(netBuffers)
  ldi xh, HIGH(netBuffers)
  m_fixedbuf_reserve NET_BUFFERS_SIZE, NET_BUFFERS_NUM
  brcc NET_Buffer_Alloc_end
  ldi r17, (1<<NET_IFACE_BUFFER_INUSE_BIT)
  st X, r17
NET_Buffer_Alloc_end:
  ret
; @end



; ---------------------------------------------------------------------------
; @routine NET_Buffer_ReleaseByAddr @global
;
; @param X pointer to start of buffer
; @clobbers R16

NET_Buffer_ReleaseByAddr:
  m_fixedbuf_release
  ret
; @end



; ---------------------------------------------------------------------------
; @routine NET_Buffer_ReleaseByNum @global
;
; @param r16 buffer number
; @clobbers X (R16)

NET_Buffer_ReleaseByNum:
  rcall NET_Buffer_Locate          ; (R16, X)
  brcc NET_Buffer_ReleaseByNum_end
  rcall NET_Buffer_ReleaseByAddr   ; (R16)
NET_Buffer_ReleaseByNum_end:
  ret
; @end



; ---------------------------------------------------------------------------
; @routine NET_Buffer_Locate
;
; Get position of a given buffer.
;
; CAVE: need to change this routine if UART_HW_FIXEDBUFFERS_SIZE is changed!
;
; @return CFLAG set if okay, cleared on error
; @return X points to start of buffer with the given num
; @param r16 buffer num (0-max)
; @clobbers r17

NET_Buffer_Locate:
  cpi r16, NET_BUFFERS_NUM
  brcc NET_Buffer_Locate_end ; out of range
  mov xh, r16  ; * 256
  clr xl
  lsr xh       ; *128
  ror xl
  lsr xh       ; *64
  ror xl
  lsr xh       ; *32
  ror xl
  ldi r17, LOW(netBuffers)
  add xl, r17
  ldi r17, HIGH(netBuffers)
  adc xh, r17
  sec
NET_Buffer_Locate_end:
  ret
; @end



; ---------------------------------------------------------------------------
; @routine NET_Buffer_CountUsed
;
; @return r16 number of buffers in use
; @param X pointer to start of buffers
; @param %0 constant maxBytes per buffer (including statusbyte in front)
; @param %1 constant maxBuffers
; @clobbers r16, r17, r18, X

NET_Buffer_CountUsed:
  ldi xl, LOW(netBuffers)
  ldi xh, HIGH(netBuffers)
  m_fixedbuf_count_used NET_BUFFERS_SIZE, NET_BUFFERS_NUM
  ret
; @end