Dear Reinhard Meyer,
In message <4c7c9b85.6080...@emk-elektronik.de> you wrote:
>
> making the change to the union, I also realized that
>
> /* Copy from memory into linebuf and print hex values */
> for (i = 0; i < linelen; i++) {
> uint32_t x;
> if (width == 4)
> x = lb.u32[i] = *(volatile uint32_t *)data;
> else if (width == 2)
> x = lb.u16[i] = *(volatile uint16_t *)data;
> else
> x = lb.u8[i] = *(volatile uint8_t *)data;
> printf(" %0*x", width * 2, x);
> data += width;
> }
>
> is still a bit "ugly". What about:
>
> union data {
> u_int32_t *u32;
> u_int16_t *u16;
> u_int8_t *u8;
> void *v;
> } dp;
> dp.v = data;
This is missing the extremely important "volatile" attribute.
> /* Copy from memory into linebuf and print hex values */
> for (i = 0; i < linelen; i++) {
> if (width == 4)
> x = lb.u32[i] = *(dp.u32)++;
> else if (width == 2)
> x = lb.u16[i] = *(dp.u16)++;
> else
> x = lb.u8[i] = *(dp.u8)++;
> printf(" %0*x", width * 2, x);
> }
>
> optionally calling printf inside the if:
>
> /* Copy from memory into linebuf and print hex values */
> for (i = 0; i < linelen; i++) {
> if (width == 4)
> printf(" %08x", lb.u32[i] = *(dp.u32)++);
> else if (width == 2)
> printf(" %04x", lb.u16[i] = *(dp.u16)++);
> else
> printf(" %02x", lb.u8[i] = *(dp.u8)++);
> }
This will increase the code size, right?
> maybe it would even be more effective to swap for and if:
>
> /* Copy from memory into linebuf and print hex values */
> if (width == 4) {
> for (i = 0; i < linelen; i++)
> printf(" %08x", lb.u32[i] = *(dp.u32)++);
> } else if (width == 2) {
> for (i = 0; i < linelen; i++)
> printf(" %04x", lb.u16[i] = *(dp.u16)++);
> } else {
> for (i = 0; i < linelen; i++)
> printf(" %02x", lb.u8[i] = *(dp.u8)++);
> }
This is much harder to read and to understand. NAK.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de
"In the face of entropy and nothingness, you kind of have to pretend
it's not there if you want to keep writing good code."
- Karl Lehenbauer
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