154 lines
6.2 KiB
Ruby
154 lines
6.2 KiB
Ruby
require "vm/c_machine"
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require_relative "stack_instruction"
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require_relative "logic_instruction"
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require_relative "move_instruction"
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require_relative "compare_instruction"
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require_relative "memory_instruction"
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require_relative "call_instruction"
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require_relative "constants"
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module Arm
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class ArmMachine < Vm::CMachine
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def integer_less_or_equal block , first , right
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block.add_code cmp( first , right: right )
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Vm::Bool.new
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end
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def integer_plus block , result , first , right
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block.add_code add( result , left: first , :extra => right )
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result
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end
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def integer_minus block , result , first , right
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block.add_code sub( result , left: first , :extra => right )
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result
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end
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def integer_load block , first , right
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block.add_code mov( first , right: right )
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first
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end
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def integer_move block , first , right
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block.add_code mov( first , right: right )
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first
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end
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def string_load block , str_lit , reg
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block.add_code add( "r#{reg}".to_sym , :extra => str_lit ) #right is pc, implicit
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#second arg is a hack to get the stringlength without coding
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block.add_code mov( "r#{reg+1}".to_sym , right: str_lit.length )
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str_lit
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end
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def function_call into , call
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raise "Not CallSite #{call.inspect}" unless call.is_a? Vm::CallSite
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raise "Not linked #{call.inspect}" unless call.function
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into.add_code call( call.function , {})
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call.function.return_type
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end
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def main_start entry
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entry.add_code mov( :fp , right: 0 )
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end
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def main_exit exit
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syscall(exit , 1)
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exit
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end
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def function_entry block, f_name
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# entry.add_code push( :regs => [:lr] )
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block
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end
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def function_exit entry , f_name
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entry.add_code mov( :pc , right: :lr )
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end
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# assumes string in r0 and r1 and moves them along for the syscall
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def write_stdout block
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block.add_code mov( :r2 , right: :r1 )
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block.add_code mov( :r1 , right: :r0 )
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block.add_code mov( :r0 , right: 1 ) # 1 == stdout
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syscall( block , 4 )
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end
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# make a string out of the integer.
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# as we don't have memory management yet, we have to pass the string in (ouch)
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# in a weird twist the string is actually a string, while we really use its address.
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# this works as the program will save any strings used onto the assmbly (thus creating a global)
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def integer_to_s block , string
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block.add_code push( [:lr ] , {} ) #return address
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# pin data, so no saving when recursing
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str_addr = Vm::Integer.new(0)
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block.add_code add( str_addr , left: string)
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# need to create a block to do the actual utoa, which is recursive
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tos = utoa(str_addr)
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block.add_code call( tos , {} ) # call the workers in
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block.add_code pop( [:pc] , {} ) # return
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block.add_code(tos) # and then add the new block to actually generate code
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end
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def utoa str_addr
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number = Vm::Integer.new(str_addr.register + 1)
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remainder = Vm::Integer.new( number.register + 1)
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tos = Vm::Block.new("i_to_s")
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#STMFD sp!, {r9, r10, lr} #function entry save working regs (for recursion)
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tos.add_code push( [:lr ] , {} ) #and the return address.
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# MOV r9, r1 # preserve arguments over following
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# MOV r10, r2 # function calls
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# BL udiv10 # r1 = r1 / 10
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div10( tos , number , remainder )
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# ADD r10, r10, 48 #'0' # make char out of digit (by using ascii encoding)
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tos.add_code add( remainder , left: remainder , right: 48 )
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#STRB r10, [r1], 1 # store digit at end of buffer
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tos.add_code strb( remainder , right: str_addr ) #and increment TODO check
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# CMP r1, #0 # quotient non-zero?
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tos.add_code cmp( number , right: 0 )
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#BLNE utoa # conditional recursive call to utoa
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tos.add_code callne( tos , {} )
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#LDMFD sp!, {r9, r10, pc} # function exit - restore and return
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tos.add_code pop( [:pc] , {} )
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return tos
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end
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private
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# the number (a Vm::integer) is (itself) divided by 10, ie overwritten by the result
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# and the remainder is overwritten (ie an out argument)
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# not really a function, more a macro, hence private
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def div10 block, number , remainder
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# takes argument in r1
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# returns quotient in r1, remainder in r2
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# SUB r2, r1, #10 # keep (x-10) for later
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block.add_code sub( remainder , left: number , right: 10 )
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# SUB r1, r1, r1, lsr #2
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block.add_code sub( number , left: number , right: number , shift_lsr: 2)
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# ADD r1, r1, r1, lsr #4
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block.add_code add( number , left: number , right: number , shift_lsr: 4)
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# ADD r1, r1, r1, lsr #8
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block.add_code add( number , left: number , right: number , shift_lsr: 8)
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# ADD r1, r1, r1, lsr #16
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block.add_code add( number , left: number , right: number , shift_lsr: 16)
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# MOV r1, r1, lsr #3
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block.add_code mov( remainder , left: remainder , right: remainder , shift_lsr: 3)
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# ADD r3, r1, r1, asl #2
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tmp = Vm::Integer.new( remainder.register + 1)
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block.add_code add( tmp , left: number , right: number , shift_lsl: 2)
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# SUBS r2, r2, r3, asl #1 # calc (x-10) - (x/10)*10
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block.add_code sub( remainder , left: remainder , right: tmp , shift_lsl: 1 , update_status: 1)
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# ADDPL r1, r1, #1 # fix-up quotient
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block.add_code add( number , left: number, right: 1 , condition_code: :pl )
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# ADDMI r2, r2, #10 # fix-up remainder
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block.add_code add( remainder , left: remainder , right: 10 , condition_code: :mi )
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end
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def syscall block , num
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block.add_code mov( :r7 , right: num )
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block.add_code swi( 0 , {})
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Vm::Integer.new(0) #small todo, is this actually correct for all (that they return int)
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end
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end
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end |