[PATCH] arm/strlen-thumb2-Os.S: Correct assembly syntax for ldrb instruction
Keith Packard via Newlib <[email protected]>
| Newsgroups | gmane.comp.lib.newlib |
|---|---|
| Message-ID | <[email protected]> |
We want to use a post-indexed addressing mode (which means use the original register contents as the address, then increment that register) which is only valid in Encoding T3 of the LDRB instruction. According to the ARMv7-M Architecture Reference Manual, the assembly syntax for Encoding T3 does not include the '.W' width specifier as that is used to specify Encoding T2, presumably to provide a wider immediate field for possible relocations. GAS allows the .W specifier for this addressing mode and generates identical output with and without it. clang does not allow the .W specifier for this addressing mode, so removing it offers wider portability and closer adherance to the ARM assembly syntax specification. Signed-off-by: Keith Packard <[email protected]> --- newlib/libc/machine/arm/strlen-thumb2-Os.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/newlib/libc/machine/arm/strlen-thumb2-Os.S b/newlib/libc/machine/arm/strlen-thumb2-Os.S index 961f41a0a..aed8adf33 100644 --- a/newlib/libc/machine/arm/strlen-thumb2-Os.S +++ b/newlib/libc/machine/arm/strlen-thumb2-Os.S @@ -45,7 +45,7 @@ def_fn strlen p2align=1 mov r3, r0 -1: ldrb.w r2, [r3], #1 +1: ldrb r2, [r3], #1 cmp r2, #0 bne 1b subs r0, r3, r0 -- 2.26.2