Mischief reported a crash with on arm with winwatch when closing all windows excluding those ignored through the -e flag. Cinap_lenrek narrowed the problem down to a bug in the 5l linker: it generates incorrect code when using the conditional operator and dividing. A minimal test case is the following:
term% cat foo.c #include <u.h> #include <libc.h> void main(void) { int i, j, k; i = 1; j = 0; k = j <= 0 ? 1 : 2/i; print("%d\n", k); exits(nil); } The output of asm(main) in acid is: acid: asm(main) main 0x00001020 MOVW.W R14,#-0x18(R13) main+0x4 0x00001024 MOVW $#0x1,R1 main+0x8 0x00001028 MOVW $#0x0,R2 main+0xc 0x0000102c CMP.S $#0x0,R2 main+0x10 0x00001030 MOVW.LE R1,R3 main+0x14 0x00001034 MOVW.GT $#0x2,R3 main+0x18 0x00001038 SUB.GT $#0x8,R13,R13 main+0x1c 0x0000103c MOVW R1,#0x4(R13) main+0x20 0x00001040 MOVW R3,R11 main+0x24 0x00001044 BL _div main+0x28 0x00001048 MOVW R11,R3 main+0x2c 0x0000104c ADD $#0x8,R13,R13 main+0x30 0x00001050 MOVW $#0x7080,R0 main+0x34 0x00001054 MOVW R3,#0x8(R13) main+0x38 0x00001058 BL print main+0x3c 0x0000105c MOVW $#0x0,R0 main+0x40 0x00001060 BL exits main+0x44 0x00001064 RET.P #0x18(R13) The problem is that the division at main+0x24 happens regardless of the comparison. The output from the compiler is correct, however: term% 5c -S foo.c TEXT main+0(SB),0,$20 MOVW $1,R1 MOVW $0,R2 CMP $0,R2, MOVW.LE R1,R3 MOVW.GT $2,R3 DIV.GT R1,R3,R3 MOVW $.string<>+0(SB),R0 MOVW R3,8(R13) BL ,print+0(SB) MOVW $0,R0 BL ,exits+0(SB) RET , DATA .string<>+0(SB)/8,$"%d\n\z\z\z\z\z" GLOBL .string<>+0(SB),$8 END , A (temporary) workaround for this is using an if-else statement, for which the linker generates correct code. -- pap