memlayout.nim

# The MIT License (MIT)
# 
# Copyright (c) 2015 Kashyap
# 
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# SOFTWARE.

import types
import unsigned

const EXTMEM*   = Address(0x0fffff)            # Start of extended memory
const PHYSTOP*  = Address(0xE000000)           # Top physical memory
const DEVSPACE* = Address(0xFE000000)          # Other devices are at high addresses

# Key addresses for address space layout (see kmap in vm.c for layout)

const KERNBASE* = Address(0xFFFFFFFF80000000)  # First kernel virtual address
const DEVBASE*  = Address(0xFFFFFFFF40000000)  # First device virtual address
const KERNLINK* = Address(KERNBASE + EXTMEM) # Address where kernel is linked

proc v2p*(a: Address): Address =
  a - KERNBASE

proc p2v*(a: Address): Address =
  a + KERNBASE

proc V2P*(a: Address): Address =
  a - KERNBASE

proc P2V*(a: Address): Address =
  a + KERNBASE

proc IO2V*(a: Address): Address =
  a + DEVBASE - DEVSPACE


proc V2P_WO*(a: Address): Address =
  a - KERNBASE

proc P2V_WO*(a: Address): Address =
  a + KERNBASE