Greetings, Assembly code below prints a Hello message on stdout under Linux. It is a simple call to Write system call while the address of my_str is loaded and passed via ABI conventions.
*However, if you uncomment the second line, we will face an issue and no prints happen. Can we review this:* cat > main.s .data *#my_var1: .int 1 #* my_str: .asciz "Hello\n" .text .global _start print: addi sp, sp, -40 sd ra, 0(sp) sd a0, 8(sp) sd a1, 16(sp) sd a2, 24(sp) sd a7, 32(sp) li a0, 1 la a1, my_str li a2, 6 li a7, 64 ecall ld ra, 0(sp) ld a0, 8(sp) ld a1, 16(sp) ld a2, 24(sp) ld a7, 32(sp) addi sp, sp, 40 ret _start: call print li a0, 0 li a7, 93 ecall ######## [root@fedora-riscv ~]# as -o main.o main.s; ld -o main main.o; ./main Hello *If you uncomment the second line (my_var1: .int 1), the program will no longer print anything!!!*: [root@fedora-riscv ~]# rm -f main.o main [root@fedora-riscv ~]# as -o main.o main.s; ld -o main main.o; ./main [root@fedora-riscv ~]# ###### Please note, all we did was just to use .int directive in the data section and very oddly we no longer can access my_str ... I tried to use .align 3 to make sure we have 64 bit alignment with no luck ... ###### [root@fedora-riscv ~]# as --version GNU assembler version 2.39-4.fc37 Copyright (C) 2022 Free Software Foundation, Inc. This program is free software; you may redistribute it under the terms of the GNU General Public License version 3 or later. This program has absolutely no warranty. This assembler was configured for a target of `riscv64-redhat-linux'. [root@fedora-riscv ~]# cat /proc/cpuinfo processor : 0 hart : 5 isa : rv64imafdch_sstc_zicbom_zihintpause mmu : sv57 processor : 1 hart : 0 isa : rv64imafdch_sstc_zicbom_zihintpause mmu : sv57 processor : 2 hart : 1 isa : rv64imafdch_sstc_zicbom_zihintpause mmu : sv57 processor : 3 hart : 2 isa : rv64imafdch_sstc_zicbom_zihintpause mmu : sv57 processor : 4 hart : 3 isa : rv64imafdch_sstc_zicbom_zihintpause mmu : sv57 processor : 5 hart : 4 isa : rv64imafdch_sstc_zicbom_zihintpause mmu : sv57 [root@fedora-riscv ~]# uname -a Linux fedora-riscv 6.0.10-300.0.riscv64.fc37.riscv64 #1 SMP Sun Nov 27 19:08:44 GMT 2022 riscv64 riscv64 riscv64 GNU/Linux System is vanilla Fedora 37 running under the QEMU emulator version 8.0.2 for RISC-V 64. Thank you, David
