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cr6502.py
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cr6502.py
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# ------------------------------------------------------------------------------
#
# cr6502.py
#
# Package module file for the SB-Assembler sbasm
# See www.sbprojects.net for details
#
# Author: San Bergmans
# Date : 2015-12-21
#
# Cross Overlay for the 6502 devices
#
# ------------------------------------------------------------------------------
import sys
import os
import assem
import dec
import errors
import target
crossversion = '3.01.02'
minversion = '3.01.00'
sweet16 = False # Sweet16 mode if True
Sweet16_Mnemonics = {} # Extra instruction set for Sweet16
modelinex = 2
# ------------------------------------------------------------------------------
def Help():
print('Tell a little story about this cross overlay')
# instruction length in clock cycles
# * add 1 if page boundary is crossed
# ** add 1 if branch occurs to same page
# add 2 if branch occurs to next page
# The CMOS chips have different timings.
# Especially if the D flag is set, most data instructions take 1 cycle
# more.
# Also if indexes cross a page boundary the instruction takes 1 cycle more.
# The document W65C02S contains some errors/inconsistencies regarding
# timings
# ------------------------------------------------------------------------------
def CrossInit():
"""
Initialize this cross overlay.
Mainly create two dictionaries. One holding all 6502 instructions and
one holding the Sweet16 instructions.
Set default mode to 6502 instructions.
Also add one extra warning for the 6502 JMP (IND) bug
"""
global Asm, Flags, Error_List, sweet16, Sweet16_Mnemonics, modelindex
assem.CheckVersions(crossversion, minversion)
sweet16 = False
if dec.Cross.Name == 'cr6502':
# Index to 6502 instruction times
modelindex = 2
else:
# Index to 65C02 and 65SC02 instruction times
modelindex = 3
# The instructions directory contains a tuple with:
# function which handles this opcode,
# integer value of opcode, or a tupple with opcodes
# string or tupple with 6502 cycle time(s)
# string or tupple with 65C02 cycle time(s)
# If the final cycle time is 0 that particular instruction
# or addressing mode doesn't exist for the selected
# processor.
dec.Asm.Instructions = {
'BRK' : (Implied, 0x00, '7', '7'),
'CLC' : (Implied, 0x18, '2', '2'),
'CLD' : (Implied, 0xD8, '2', '2'),
'CLI' : (Implied, 0x58, '2', '2'),
'CLV' : (Implied, 0xB8, '2', '2'),
'DEA' : (Implied, 0x3A, '0', '2'),
'DEX' : (Implied, 0xCA, '2', '2'),
'DEY' : (Implied, 0x88, '2', '2'),
'INA' : (Implied, 0x1A, '0', '2'),
'INX' : (Implied, 0xE8, '2', '2'),
'INY' : (Implied, 0xC8, '2', '2'),
'NOP' : (Implied, 0xEA, '2', '2'),
'PHA' : (Implied, 0x48, '3', '3'),
'PHP' : (Implied, 0x08, '3', '3'),
'PHX' : (Implied, 0xDA, '0', '3'),
'PHY' : (Implied, 0x5A, '0', '3'),
'PLA' : (Implied, 0x68, '4', '4'),
'PLP' : (Implied, 0x28, '4', '4'),
'PLX' : (Implied, 0xFA, '0', '4'),
'PLY' : (Implied, 0x7A, '0', '4'),
'RTI' : (Implied, 0x40, '6', '6'),
'RTS' : (Implied, 0x60, '6', '6'),
'SEC' : (Implied, 0x38, '2', '2'),
'SED' : (Implied, 0xF8, '2', '2'),
'SEI' : (Implied, 0x78, '2', '2'),
'STP' : (Implied, 0xDB, '0', '3'),
'TAX' : (Implied, 0xAA, '2', '2'),
'TAY' : (Implied, 0xA8, '2', '2'),
'TSX' : (Implied, 0xBA, '2', '2'),
'TXA' : (Implied, 0x8A, '2', '2'),
'TXS' : (Implied, 0x9A, '2', '2'),
'TYA' : (Implied, 0x98, '2', '2'),
'WAI' : (Implied, 0xCB, '0', '3'),
'BCC' : (Branch, 0x90, '2**', '2**'),
'BCS' : (Branch, 0xB0, '2**', '2**'),
'BEQ' : (Branch, 0xF0, '2**', '2**'),
'BMI' : (Branch, 0x30, '2**', '2**'),
'BNE' : (Branch, 0xD0, '2**', '2**'),
'BPL' : (Branch, 0x10, '2**', '2**'),
'BRA' : (Branch, 0x80, '0', '2**'),
'BVC' : (Branch, 0x50, '2**', '2**'),
'BVS' : (Branch, 0x70, '2**', '2**'),
# implied, imm, zp, abs, (zp,x) (zp),y, zp,x abs,x zp,y abs,y (zp)
'ADC' : (Multi, (0x00, 0x69, 0x65, 0x6D, 0x61, 0x71, 0x75, 0x7D, 0x00,
0x79, 0x72),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'0'),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'5')
),
'ADD' : (Multi, (0x00, 0x69, 0x65, 0x6D, 0x61, 0x71, 0x75, 0x7D, 0x00,
0x79, 0x72),
('0', '4', '5', '6', '8', '5*', '6', '6*', '0', '6*',
'0'),
('0', '4', '5', '6', '8', '5*', '6', '6*', '0', '6*',
'5')
),
'AND' : (Multi, (0x00, 0x29, 0x25, 0x2D, 0x21, 0x31, 0x35, 0x3D, 0x00,
0x39, 0x32),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'0'),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'5')
),
'ASL' : (Multi, (0x0A, 0x00, 0x06, 0x0E, 0x00, 0x00, 0x16, 0x1E, 0x00,
0x00, 0x00),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0'),
('2', '0', '5', '6', '0', '0', '6', '6*', '0', '0',
'0')
),
'BIT' : (Multi, (0x00, 0x89, 0x24, 0x2C, 0x00, 0x00, 0x34, 0x3C, 0x00,
0x00, 0x00),
('0', '0', '3', '4', '0', '0', '0', '0', '0', '0',
'0'),
('0', '2', '3', '4', '0', '0', '4', '4', '0', '0',
'0')
),
'CMP' : (Multi, (0x00, 0xC9, 0xC5, 0xCD, 0xC1, 0xD1, 0xD5, 0xDD, 0x00,
0xD9, 0xD2),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'0'),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'5')
),
'CPX' : (Multi, (0x00, 0xE0, 0xE4, 0xEC, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00),
('0', '2', '3', '4', '0', '0', '0', '0', '0', '0',
'0'),
('0', '2', '3', '4', '0', '0', '0', '0', '0', '0',
'0')
),
'CPY' : (Multi, (0x00, 0xC0, 0xC4, 0xCC, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00),
('0', '2', '3', '4', '0', '0', '0', '0', '0', '0',
'0'),
('0', '2', '3', '4', '0', '0', '0', '0', '0', '0',
'0')
),
'DEC' : (Multi, (0x3A, 0x00, 0xC6, 0xCE, 0x00, 0x00, 0xD6, 0xDE, 0x00,
0x00, 0x00),
('0', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0'),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0')
),
'EOR' : (Multi, (0x00, 0x49, 0x45, 0x4D, 0x41, 0x51, 0x55, 0x5D, 0x00,
0x59, 0x52),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'0'),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'5')
),
'INC' : (Multi, (0x1A, 0x00, 0xE6, 0xEE, 0x00, 0x00, 0xF6, 0xFE, 0x00,
0x05, 0x00),
('0', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0'),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0')
),
'JMP' : (Multi, (0x00, 0x00, 0x00, 0x4C, 0x7C, 0x00, 0x00, 0x00, 0x00,
0x00, 0x6C),
('0', '0', '0', '3', '0', '0', '0', '0', '0', '0',
'5'),
('0', '0', '0', '3', '6', '0', '0', '0', '0', '0',
'6')
),
'JSR' : (Multi, (0x00, 0x00, 0x00, 0x20, 0x20, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00),
('0', '0', '0', '6', '0', '0', '0', '0', '0', '0',
'0'),
('0', '0', '0', '6', '0', '0', '0', '0', '0', '0',
'0')
),
'LDA' : (Multi, (0x00, 0xA9, 0xA5, 0xAD, 0xA1, 0xB1, 0xB5, 0xBD, 0x00,
0xB9, 0xB2),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'0'),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'5')
),
'LDX' : (Multi, (0x00, 0xA2, 0xA6, 0xAE, 0x00, 0x09, 0x00, 0x00, 0xB6,
0xBE, 0x00),
('0', '2', '3', '4', '0', '0', '0', '0', '4', '4*',
'0'),
('0', '2', '3', '4', '0', '0', '0', '0', '4', '4*',
'0')
),
'LDY' : (Multi, (0x00, 0xA0, 0xA4, 0xAC, 0x00, 0x00, 0xB4, 0xBC, 0x00,
0x00, 0x00),
('0', '2', '3', '4', '0', '0', '4', '4*', '0', '0',
'0'),
('0', '2', '3', '4', '0', '0', '4', '4*', '0', '0',
'0')
),
'LSR' : (Multi, (0x4A, 0x00, 0x46, 0x4E, 0x00, 0x00, 0x56, 0x5E, 0x00,
0x00, 0x00),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0'),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0')
),
'ORA' : (Multi, (0x00, 0x09, 0x05, 0x0D, 0x01, 0x11, 0x15, 0x1D, 0x00,
0x19, 0x12),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'0'),
('0', '2', ' 3', '4', '6', '5*', '4', '4*', '0', '4*',
'5')
),
'ROL' : (Multi, (0x2A, 0x09, 0x26, 0x2E, 0x00, 0x00, 0x36, 0x3E, 0x00,
0x00, 0x00),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0'),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0')
),
'ROR' : (Multi, (0x6A, 0x00, 0x66, 0x6E, 0x00, 0x00, 0x76, 0x7E,
0x00, 0x00, 0x00),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0'),
('2', '0', '5', '6', '0', '0', '6', '7', '0', '0',
'0')
),
'SBC' : (Multi, (0x00, 0xE9, 0xE5, 0xED, 0xE1, 0xF1, 0xF5, 0xFD, 0x00,
0xF9, 0xF2),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'0'),
('0', '2', '3', '4', '6', '5*', '4', '4*', '0', '4*',
'5')
),
'SUB' : (Multi, (0x00, 0xE9, 0xE5, 0xED, 0xE1, 0xF1, 0xF5, 0xFD, 0x00,
0xF9, 0xF2),
('0', '4', '5', '6', '8', '7*', '6', '6*', '0', '6*',
'0'),
('0', '4', '5', '6', '8', '7*', '6', '6*', '0', '6*',
'5')
),
'STA' : (Multi, (0x00, 0x00, 0x85, 0x8D, 0x81, 0x91, 0x95, 0x9D, 0x00,
0x99, 0x92),
('0', '0', '2', '4', '6', '6', '4', '5', '0', '5',
'0'),
('0', '0', '3', '4', '6', '6', '4', '5', '0', '5',
'5')
),
'STX' : (Multi, (0x00, 0x00, 0x86, 0x8E, 0x00, 0x00, 0x00, 0x00, 0x96,
0x00, 0x00),
('0', '0', '3', '4', '0', '0', '0', '0', '4', '0',
'0'),
('0', '0', '3', '4', '0', '0', '0', '0', '4', '0',
'0')
),
'STY' : (Multi, (0x00, 0x00, 0x84, 0x8C, 0x00, 0x00, 0x94, 0x00, 0x00,
0x00, 0x00),
('0', '0', '3', '4', '0', '0', '4', '0', '0', '0',
'0'),
('0', '0', '3', '4', '0', '0', '4', '0', '0', '0',
'0')
),
'STZ' : (Multi, (0x00, 0x00, 0x64, 0x9C, 0x00, 0x00, 0x74, 0x9E, 0x00,
0x00, 0x00),
('0', '0', '0', '0', '0', '0', '0', '0', '0', '0',
'0'),
('0', '0', '3', '4', '0', '0', '4', '5', '0', '0',
'0')
),
'TRB' : (Multi, (0x00, 0x00, 0x14, 0x1C, 0x00, 0x00, 0x94, 0x00, 0x00,
0x00, 0x00),
('0', '0', '0', '0', '0', '0', '0', '0', '0', '0',
'0'),
('0', '0', '5', '6', '0', '0', '4', '0', '0', '0',
'0')
),
'TSB' : (Multi, (0x00, 0x00, 0x04, 0x0C, 0x00, 0x00, 0x94, 0x00, 0x00,
0x00, 0x00),
('0', '0', '0', '0', '0', '0', '0', '0', '0', '0',
'0'),
('0', '0', '5', '6', '0', '0', '4', '0', '0', '0',
'0')
),
'BBR0': (BitMan, 0x0F, '5'),
'BBR1': (BitMan, 0x1F, '5'),
'BBR2': (BitMan, 0x2F, '5'),
'BBR3': (BitMan, 0x3F, '5'),
'BBR4': (BitMan, 0x4F, '5'),
'BBR5': (BitMan, 0x5F, '5'),
'BBR6': (BitMan, 0x6F, '5'),
'BBR7': (BitMan, 0x7F, '5'),
'BBR' : (BitMan, 0x0F, '5'),
'BBS0': (BitMan, 0x8F, '5'),
'BBS1': (BitMan, 0x9F, '5'),
'BBS2': (BitMan, 0xAF, '5'),
'BBS3': (BitMan, 0xBF, '5'),
'BBS4': (BitMan, 0xCF, '5'),
'BBS5': (BitMan, 0xDF, '5'),
'BBS6': (BitMan, 0xEF, '5'),
'BBS7': (BitMan, 0xFF, '5'),
'BBS' : (BitMan, 0x8F, '5'),
'RMB0': (BitMan, 0x07, '5'),
'RMB1': (BitMan, 0x17, '5'),
'RMB2': (BitMan, 0x27, '5'),
'RMB3': (BitMan, 0x37, '5'),
'RMB4': (BitMan, 0x47, '5'),
'RMB5': (BitMan, 0x57, '5'),
'RMB6': (BitMan, 0x67, '5'),
'RMB7': (BitMan, 0x77, '5'),
'RMB' : (BitMan, 0x07, '5'),
'SMB0': (BitMan, 0x87, '5'),
'SMB1': (BitMan, 0x97, '5'),
'SMB2': (BitMan, 0xA7, '5'),
'SMB3': (BitMan, 0xB7, '5'),
'SMB4': (BitMan, 0xC7, '5'),
'SMB5': (BitMan, 0xD7, '5'),
'SMB6': (BitMan, 0xE7, '5'),
'SMB7': (BitMan, 0xF7, '5'),
'SMB' : (BitMan, 0x87, '5')
}
Sweet16_Mnemonics = {
'BK' : (Single16, 0x0A),
'RS' : (Single16, 0x0B),
'RTN' : (Single16, 0x00),
'BR' : (Branch16, 0x01),
'BNC' : (Branch16, 0x02),
'BC' : (Branch16, 0x03),
'BP' : (Branch16, 0x04),
'BM' : (Branch16, 0x05),
'BZ' : (Branch16, 0x06),
'BNZ' : (Branch16, 0x07),
'BM1' : (Branch16, 0x08),
'BNM1': (Branch16, 0x09),
'BS' : (Branch16, 0x0C),
'SET' : (Sweet16, 0x10, 0x00),
'LD' : (Sweet16, 0x20, 0x40),
'ST' : (Sweet16, 0x30, 0x50),
'LDD' : (Sweet16, 0x00, 0x60),
'STD' : (Sweet16, 0x00, 0x70),
'POP' : (Sweet16, 0x00, 0x80),
'STP' : (Sweet16, 0x00, 0x90),
'ADD' : (Sweet16, 0xA0, 0x00),
'SUB' : (Sweet16, 0xB0, 0x00),
'POPD': (Sweet16, 0x00, 0xC0),
'CPR' : (Sweet16, 0xD0, 0x00),
'INR' : (Sweet16, 0xE0, 0x00),
'DCR' : (Sweet16, 0xF0, 0x00)
}
dec.Asm.Timing_Length = 3 # Maximum length of instruction time
errors.Error_List['6502bug'] = '6502 JMP (IND) bug at $xxFF'
dec.Asm.Memory = 0
if dec.Asm.Pass == 1:
sys.stdout.write('Loaded ' + dec.Cross.Name[2:] +
' overlay version ' + crossversion + dec.EOL)
# Allow assembled output files > 64 KB (max 32 MB for ProDOS volume)
# NOTE: This is the maximum output ADDRESS and not the max file SIZE
# i.e.
# dec.Asm.Max_Address = 0
#
# .or $100
# .db 1 ; FAIL; address $0100 > $0000
#
# .or $0
# .db 1 ; PASS; address $0000 <= $0000
#dec.Asm.Max_Address = dec.MAX16
dec.Asm.Max_Address = 0x1FFFFFF
dec.Asm.PP_TA_Factor = 1
dec.Flags.BigEndian = False
return
# ------------------------------------------------------------------------------
def CrossDirective():
"""
No extra directives for this Cross overlay
"""
return False # We didn't handle any directives
# ------------------------------------------------------------------------------
def CrossCleanUp():
"""
No need to do any cleaning.
"""
return
# ------------------------------------------------------------------------------
def CrossMnemonic():
"""
Find and decode the current mnemonic.
This may be a normal 6502 instruction, or a Sweet16 instruction depending
on the current mode.
JSR SWEET16 switches mode from 6502 to Sweet16, regardless of the value
of the lable SWEET16.
RTN switches mode back from Sweet16 to 6502.
"""
global Asm
if not sweet16:
# Parse normal 6502 mnemonics
if dec.Asm.Mnemonic in dec.Asm.Instructions:
func = dec.Asm.Instructions[dec.Asm.Mnemonic][0]
func()
else:
errors.DoError('badopco', False)
else:
# Parse Sweet16 mnemonics
if dec.Asm.Mnemonic in Sweet16_Mnemonics:
func = Sweet16_Mnemonics[dec.Asm.Mnemonic][0]
dec.Asm.Timing = '?'
func()
else:
errors.DoError('badopco', False)
# -----------------------------------------------------------------------------
def MissingOperand():
"""
An operand must follow. Raise an error if it's not.
"""
if dec.Asm.Parse_Pointer == 0:
errors.DoError('missoper', False)
return True
else:
return False
# -----------------------------------------------------------------------------
def NoMore():
"""
No more operands shoudl follow. Raise a warning if more parameters follow.
"""
if assem.MoreParameters():
errors.DoWarning('extrign', False)
# -----------------------------------------------------------------------------
def Implied():
"""
Handle implied addressing mode.
Simply save the opcode and we're done with it.
"""
global Asm
dec.Asm.Timing = dec.Asm.Instructions[dec.Asm.Mnemonic][modelindex]
if dec.Asm.Timing != '0':
target.CodeByte(dec.Asm.Instructions[dec.Asm.Mnemonic][1])
else:
errors.DoError('badopco', False)
# -----------------------------------------------------------------------------
def Branch():
"""
Handle branch instructions.
Displacement is destinaiton - current address - 2
"""
global Asm
dec.Asm.Timing = dec.Asm.Instructions[dec.Asm.Mnemonic][modelindex]
if dec.Asm.Timing != '0':
if MissingOperand():
return
value = assem.EvalExpr()
offset = value[0] - dec.Asm.BOL_Address - 2
if dec.Asm.Pass == 2 and (offset < -128 or offset > 127):
errors.DoError('range', False)
target.CodeByte(dec.Asm.Instructions[dec.Asm.Mnemonic][1])
target.CodeByte(offset)
NoMore()
else:
errors.DoError('badopco', False)
# -----------------------------------------------------------------------------
def Multi():
"""
Handle all other mnemonics of the 6502 instructionset.
Each addressing mode has a separate entry in the opcode tupple.
If the opcode is 0x00 the particular instruction is not available
on the selected model.
If the cycle length is '0' the particular addressing mode is not
supported.
The model is selected by calling either the 6502 overlay, or the
65c02 or 65sc02 overlays.
"""
global Asm, sweet16
if modelindex == 2 and (dec.Asm.Mnemonic in ('STZ', 'TRB', 'TSB')):
errors.DoError('badopco', False)
return
instructions = dec.Asm.Instructions[dec.Asm.Mnemonic][1]
ctimes = dec.Asm.Instructions[dec.Asm.Mnemonic][modelindex]
operandbegin = dec.Asm.Parse_Pointer
# Does implied addressing exist for this instruction?
optional = dec.Asm.Optional
pointer = dec.Asm.Parse_Pointer
if instructions[0] != 0 and ctimes[0] != '0':
if optional and \
(dec.Asm.Parse_Line[operandbegin:operandbegin+2].upper() ==
"A "):
optional = False
if optional is False:
# No operand followed, use implied addressing mode
dec.Asm.Timing = ctimes[0]
target.CodeByte(instructions[0])
return
if MissingOperand():
return
# There are two compound instructions, save prefix for them first
if dec.Asm.Mnemonic == 'ADD':
target.CodeByte(0x18)
if dec.Asm.Mnemonic == 'SUB':
target.CodeByte(0x38)
nowchar = assem.NowChar().upper()
# Is it immediate addressing mode?
if nowchar in '#/=\\':
if instructions[1] == 0 or ctimes[1] == '0':
errors.DoError('badoper', False)
return
prefix = assem.NowChar(True)
value = assem.EvalExpr()
dec.Asm.Timing = ctimes[1]
if prefix == '#':
operand = value[0]
elif prefix == '/':
operand = value[0] >> 8
elif prefix == '=':
operand = value[0] >> 16
else:
operand = value[0] >> 24
target.CodeByte(instructions[1])
target.CodeByte(operand)
NoMore()
return
# Is it some kind if indirect mode?
if nowchar == '(':
assem.IncParsePointer()
value = assem.EvalExpr()
if assem.NowChar() == ')':
# It must be (ZP),Y mode now, or is it JMP (IND) ?
# On the CMOS models it can also be (ZP)
assem.IncParsePointer()
if assem.MoreParameters():
# It must be (zp),y now
opcode = instructions[5]
if (opcode != 0) and (assem.NowChar(True).upper() == 'Y'):
dec.Asm.Timing = ctimes[5]
target.CodeByte(opcode)
target.CodeByte(value[0])
if dec.Asm.Pass == 2 and ((value[0] >> 8) != 0):
errors.DoError('range', False)
NoMore()
return
else:
errors.DoError('badoper', False)
else:
# It is (zp), or (abs) in case of JMP now
opcode = instructions[10]
dec.Asm.Timing = ctimes[10]
if dec.Asm.Mnemonic == "JMP":
# It's JMP (IND)
target.CodeByte(opcode)
target.CodeWord(value[0])
if dec.Asm.Pass == 2 and ((value[0] >> 16) != 0):
errors.DoError('range', False)
if ((value[0] & 255) == 255) and modelindex == 2:
# Give warning to user about the 6502 JMP (IND) bug
errors.DoWarning('6502bug', False)
NoMore()
return
else:
# It's (zp) now
if ctimes[10] == 0:
errors.DoError('badoper', False)
return
target.CodeByte(opcode)
target.CodeByte(value[0])
if dec.Asm.Pass == 2 and ((value[0] >> 8) != 0):
errors.DoError('range', False)
NoMore()
return
return
# It must be (ZP,X) mode now
opcode = instructions[4]
if (opcode != 0 and ctimes[4] != '0') and assem.MoreParameters() \
and (assem.NowChar(True).upper() == 'X') and \
(assem.NowChar(True).upper() == ')'):
dec.Asm.Timing = ctimes[4]
target.CodeByte(opcode)
if dec.Asm.Mnemonic == "JMP":
target.CodeWord(value[0])
if dec.Asm.Pass == 2 and ((value[0] >> 16) != 0):
errors.DoError('range', False)
else:
target.CodeByte(value[0])
if dec.Asm.Pass == 2 and ((value[0] >> 8) != 0):
errors.DoError('range', False)
NoMore()
else:
errors.DoError('badoper', False)
return
# May now be ZP, ABS, ZP,X ABS,X ZP,Y or ABS,Y
if nowchar in '<>':
# Forced ZP or ABS prefix given
prefix = nowchar
assem.IncParsePointer()
else:
prefix = '' # We have no preference, let the assembler decide
value = assem.EvalExpr()
if prefix == '':
if value[1]:
# A forward referenced label is used, force absolute mode
prefix = '>'
else:
# Now decide if ZP is still possible
if (value[0] >> 8) == 0:
prefix = '<'
else:
prefix = '>'
if not (assem.MoreParameters()):
# It's normal ZP or ABS addressing mode
if prefix == '<':
index = 2
else:
index = 3
else:
# It's ZP or ABS indexed with X or Y now
nowchar = assem.NowChar(True).upper()
if nowchar == 'X':
index = 6
elif nowchar == 'Y':
index = 8
else:
errors.DoError('badoper', False)
return
if prefix == '>':
index = index + 1
if prefix == '<' and instructions[index] == 0:
# ZP wanted, but doesn't exist, use ABS instead
prefix = '>'
index = index + 1
if instructions[index] == 0 or ctimes[index] == '0':
errors.DoError('badoper', False)
return
target.CodeByte(instructions[index])
dec.Asm.Timing = ctimes[index]
if prefix == '<':
target.CodeByte(value[0])
address = value[0] >> 8
else:
target.CodeWord(value[0])
address = value[0] >> 16
if dec.Asm.Mnemonic == 'JSR':
# See if it's JSR SWEET16
if dec.Asm.Parse_Line[operandbegin:operandbegin+8].upper() == \
'SWEET16 ':
sweet16 = True
if dec.Asm.Pass == 2 and address != 0:
errors.DoError('range', False)
NoMore()
return
# -----------------------------------------------------------------------------
def BitMan():
"""
The Bit Manipulation instructions are unique to the CMOS devices.
Even so, not all devices know them.
It's up to the user to make sure the device supports these instructions
or not.
Two syntax versions exist. One where the bit number is part of the
mnemonic, and one where the bit number is the first parameter in the
parameter field.
"""
global Asm
if modelindex == 2 and (dec.Asm.Mnemonic in ('STZ', 'TRB', 'TSB')):
errors.DoError('badopco', False)
return
opcode = dec.Asm.Instructions[dec.Asm.Mnemonic][1]
dec.Asm.Timing = dec.Asm.Instructions[dec.Asm.Mnemonic][2]
if MissingOperand():
return
if len(dec.Asm.Mnemonic) == 3:
# Alternative syntax used, with separate bit number
value = assem.EvalExpr()
if dec.Asm.Pass == 2 and (value[0] >> 3) != 0:
errors.DoError('range', False)
opcode = opcode + ((value[0] & 7) << 4)
if not assem.MoreParameters():
errors.DoError('missoper', False)
return
value = assem.EvalExpr()
if dec.Asm.Pass == 2 and (value[0] >> 8) != 0:
errors.DoError('range', False)
address = value[0]
if dec.Asm.Mnemonic[0] == 'B':
# Branch instructions
if not assem.MoreParameters():
errors.DoError('missoper', False)
return
value = assem.EvalExpr()
offset = value[0] - dec.Asm.BOL_Address - 3
if dec.Asm.Pass == 2 and (offset < -128 or offset > 127):
errors.DoError('range', False)
target.CodeByte(opcode)
target.CodeByte(address)
target.CodeByte(offset)
else:
# Set/Reset memory bit instructions
target.CodeByte(opcode)
target.CodeByte(address)
NoMore()
# -----------------------------------------------------------------------------
def Single16():
"""
Handle Implied Sweet16 instructions.
The only difference is that RTN terminates Sweet16 mode.
"""
global Asm, sweet16
target.CodeByte(Sweet16_Mnemonics[dec.Asm.Mnemonic][1])
if dec.Asm.Mnemonic == 'RTN':
sweet16 = False
# -----------------------------------------------------------------------------
def Branch16():
"""
Handle branch instructions.
Displacement is destinaiton - current address - 2
"""
global Asm
if MissingOperand():
return
value = assem.EvalExpr()
offset = value[0] - dec.Asm.BOL_Address - 2
if dec.Asm.Pass == 2 and (offset < -128 or offset > 127):
errors.DoError('range', False)
target.CodeByte(Sweet16_Mnemonics[dec.Asm.Mnemonic][1])
target.CodeByte(offset)
NoMore()
# -----------------------------------------------------------------------------
def Sweet16():
"""
Handle remaining Sweet16 instructions. They all expect a register number,
some accept an indirect register number. Only the SET instruction also
expects a 16 bit target address.
Registers are numbered from 0 to 15. If you want to use R0 to R15 instead
assign labels to the 16 register numbers.
"""
global Asm
if MissingOperand():
return
if assem.NowChar() == '@':
assem.IncParsePointer()
opcode = Sweet16_Mnemonics[dec.Asm.Mnemonic][2]
else:
opcode = Sweet16_Mnemonics[dec.Asm.Mnemonic][1]
if opcode == 0:
errors.DoError('badopco', False)
return
value = assem.EvalExpr()
if dec.Asm.Pass == 2 and (value[0] >> 4) != 0:
errors.DoError('range', False)
opcode = opcode + (value[0] & 15)
target.CodeByte(opcode)
if dec.Asm.Mnemonic == 'SET':
if assem.MoreParameters():
value = assem.EvalExpr()
target.CodeWord(value[0])
else:
errors.DoError('missoper', False)
NoMore()
# -----------------------------------------------------------------------------
if __name__ == '__main__':
print("")
print("This is a python module, it's not a program.")
print("This module is part of the sbasm package.")
print("Run sbasm instead.")
print("")