Blackfin SPORT UART: rewrite inline assembly
Mike Frysinger [Thu, 11 Jun 2009 12:37:11 +0000 (13:37 +0100)]
Hopefuly the new version is easier to read, but in the process it declares
proper clobber lists and better constraints so that GCC can do a better
job at allocating free registers.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/bfin_sport_uart.c

index 6687ccd..34b4ae0 100644 (file)
@@ -101,15 +101,16 @@ static inline void tx_one_byte(struct sport_uart_port *up, unsigned int value)
 {
        pr_debug("%s value:%x\n", __func__, value);
        /* Place a Start and Stop bit */
-       __asm__ volatile (
-               "R2 = b#01111111100;\n\t"
-               "R3 = b#10000000001;\n\t"
-               "%0 <<= 2;\n\t"
-               "%0 = %0 & R2;\n\t"
-               "%0 = %0 | R3;\n\t"
-               :"=r"(value)
-               :"0"(value)
-               :"R2", "R3");
+       __asm__ __volatile__ (
+               "R2 = b#01111111100;"
+               "R3 = b#10000000001;"
+               "%0 <<= 2;"
+               "%0 = %0 & R2;"
+               "%0 = %0 | R3;"
+               : "=d"(value)
+               : "d"(value)
+               : "ASTAT", "R2", "R3"
+       );
        pr_debug("%s value:%x\n", __func__, value);
 
        SPORT_PUT_TX(up, value);
@@ -118,27 +119,30 @@ static inline void tx_one_byte(struct sport_uart_port *up, unsigned int value)
 static inline unsigned int rx_one_byte(struct sport_uart_port *up)
 {
        unsigned int value, extract;
+       u32 tmp_mask1, tmp_mask2, tmp_shift, tmp;
 
        value = SPORT_GET_RX32(up);
        pr_debug("%s value:%x\n", __func__, value);
 
        /* Extract 8 bits data */
-       __asm__ volatile (
-               "R5 = 0;\n\t"
-               "P0 = 8;\n\t"
-               "R1 = 0x1801(Z);\n\t"
-               "R3 = 0x0300(Z);\n\t"
-               "R4 = 0;\n\t"
-               "LSETUP(loop_s, loop_e) LC0 = P0;\nloop_s:\t"
-               "R2 = extract(%1, R1.L)(Z);\n\t"
-               "R2 <<= R4;\n\t"
-               "R5 = R5 | R2;\n\t"
-               "R1 = R1 - R3;\nloop_e:\t"
-               "R4 += 1;\n\t"
-               "%0 = R5;\n\t"
-               :"=r"(extract)
-               :"r"(value)
-               :"P0", "R1", "R2","R3","R4", "R5");
+       __asm__ __volatile__ (
+               "%[extr] = 0;"
+               "%[mask1] = 0x1801(Z);"
+               "%[mask2] = 0x0300(Z);"
+               "%[shift] = 0;"
+               "LSETUP(.Lloop_s, .Lloop_e) LC0 = %[lc];"
+               ".Lloop_s:"
+               "%[tmp] = extract(%[val], %[mask1].L)(Z);"
+               "%[tmp] <<= %[shift];"
+               "%[extr] = %[extr] | %[tmp];"
+               "%[mask1] = %[mask1] - %[mask2];"
+               ".Lloop_e:"
+               "%[shift] += 1;"
+               : [val]"=d"(value), [extr]"=d"(extract), [shift]"=d"(tmp_shift), [tmp]"=d"(tmp),
+                 [mask1]"=d"(tmp_mask1), [mask2]"=d"(tmp_mask2)
+               : "d"(value), [lc]"a"(8)
+               : "ASTAT", "LB0", "LC0", "LT0"
+       );
 
        pr_debug("      extract:%x\n", extract);
        return extract;