1; Options for the ATMEL AVR port of the compiler. 2 3; Copyright (C) 2005-2022 Free Software Foundation, Inc. 4; 5; This file is part of GCC. 6; 7; GCC is free software; you can redistribute it and/or modify it under 8; the terms of the GNU General Public License as published by the Free 9; Software Foundation; either version 3, or (at your option) any later 10; version. 11; 12; GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13; WARRANTY; without even the implied warranty of MERCHANTABILITY or 14; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15; for more details. 16; 17; You should have received a copy of the GNU General Public License 18; along with GCC; see the file COPYING3. If not see 19; <http://www.gnu.org/licenses/>. 20 21mcall-prologues 22Target Mask(CALL_PROLOGUES) 23Use subroutines for function prologues and epilogues. 24 25mmcu= 26Target RejectNegative Joined Var(avr_mmcu) MissingArgError(missing device or architecture after %qs) 27-mmcu=MCU Select the target MCU. 28 29mgas-isr-prologues 30Target Var(avr_gasisr_prologues) UInteger Init(0) Optimization 31Allow usage of __gcc_isr pseudo instructions in ISR prologues and epilogues. 32 33mn-flash= 34Target RejectNegative Joined Var(avr_n_flash) UInteger Init(-1) 35Set the number of 64 KiB flash segments. 36 37mskip-bug 38Target Mask(SKIP_BUG) 39Indicate presence of a processor erratum. 40 41mrmw 42Target Mask(RMW) 43Enable Read-Modify-Write (RMW) instructions support/use. 44 45mdeb 46Target Undocumented Mask(ALL_DEBUG) 47 48mlog= 49Target RejectNegative Joined Undocumented Var(avr_log_details) 50 51mshort-calls 52Target RejectNegative Mask(SHORT_CALLS) 53Use RJMP / RCALL even though CALL / JMP are available. 54 55mint8 56Target Mask(INT8) 57Use an 8-bit 'int' type. 58 59mno-interrupts 60Target RejectNegative Mask(NO_INTERRUPTS) 61Change the stack pointer without disabling interrupts. 62 63mbranch-cost= 64Target Joined RejectNegative UInteger Var(avr_branch_cost) Init(0) Optimization 65Set the branch costs for conditional branch instructions. Reasonable values are small, non-negative integers. The default branch cost is 0. 66 67mmain-is-OS_task 68Target Mask(MAIN_IS_OS_TASK) Optimization 69Treat main as if it had attribute OS_task. 70 71morder1 72Target Undocumented Mask(ORDER_1) 73 74morder2 75Target Undocumented Mask(ORDER_2) 76 77mtiny-stack 78Target Mask(TINY_STACK) 79Change only the low 8 bits of the stack pointer. 80 81mrelax 82Target 83Relax branches. 84 85mpmem-wrap-around 86Target 87Make the linker relaxation machine assume that a program counter wrap-around occurs. 88 89maccumulate-args 90Target Mask(ACCUMULATE_OUTGOING_ARGS) 91Accumulate outgoing function arguments and acquire/release the needed stack space for outgoing function arguments in function prologue/epilogue. Without this option, outgoing arguments are pushed before calling a function and popped afterwards. This option can lead to reduced code size for functions that call many functions that get their arguments on the stack like, for example printf. 92 93mstrict-X 94Target Var(avr_strict_X) Init(0) 95When accessing RAM, use X as imposed by the hardware, i.e. just use pre-decrement, post-increment and indirect addressing with the X register. Without this option, the compiler may assume that there is an addressing mode X+const similar to Y+const and Z+const and emit instructions to emulate such an addressing mode for X. 96 97;; For rationale behind -msp8 see explanation in avr.h. 98msp8 99Target RejectNegative Var(avr_sp8) Init(0) 100The device has no SPH special function register. This option will be overridden by the compiler driver with the correct setting if presence/absence of SPH can be deduced from -mmcu=MCU. 101 102Waddr-space-convert 103Warning C Var(avr_warn_addr_space_convert) Init(0) 104Warn if the address space of an address is changed. 105 106Wmisspelled-isr 107Warning C C++ Var(avr_warn_misspelled_isr) Init(1) 108Warn if the ISR is misspelled, i.e. without __vector prefix. Enabled by default. 109 110mfract-convert-truncate 111Target Mask(FRACT_CONV_TRUNC) 112Allow to use truncation instead of rounding towards zero for fractional fixed-point types. 113 114mabsdata 115Target Mask(ABSDATA) 116Assume that all data in static storage can be accessed by LDS / STS. This option is only useful for reduced Tiny devices. 117 118mdouble= 119Target Joined RejectNegative Var(avr_double) Init(0) Enum(avr_bits_e) Save 120-mdouble=<BITS> Use <BITS> bits wide double type. 121 122mlong-double= 123Target Joined RejectNegative Var(avr_long_double) Init(0) Enum(avr_bits_e) Save 124-mlong-double=<BITS> Use <BITS> bits wide long double type. 125 126nodevicelib 127Driver Target RejectNegative 128Do not link against the device-specific library lib<MCU>.a. 129 130nodevicespecs 131Driver Target RejectNegative 132Do not use the device-specific specs file device-specs/specs-<MCU>. 133 134Enum 135Name(avr_bits_e) Type(int) 136Available BITS selections: 137 138EnumValue 139Enum(avr_bits_e) String(32) Value(32) 140 141EnumValue 142Enum(avr_bits_e) String(64) Value(64) 143