From 789b0a2eb9ae94a10abd590c91e3ae8588137e37 Mon Sep 17 00:00:00 2001 From: Jens Arnold Date: Sun, 15 Feb 2009 17:07:18 +0000 Subject: Add an unsigned 32*32->top32 bit multiply for resizing on SH1, and switch to 32 bit precision using that. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20012 a1c6a512-1295-4272-9138-f99709370657 --- apps/recorder/resize.h | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/apps/recorder/resize.h b/apps/recorder/resize.h index 4e71fb8732..d1dabaae09 100644 --- a/apps/recorder/resize.h +++ b/apps/recorder/resize.h @@ -59,7 +59,47 @@ t; \ }) #elif (CONFIG_CPU == SH7034) -#define SC_SHIFT 24 +/* multiply two unsigned 32 bit values and return the top 32 bit + * of the 64 bit result */ +static inline unsigned sc_mul32(unsigned a, unsigned b) +{ + unsigned r, t1, t2, t3; + + asm ( + "swap.w %[a], %[t1] \n" /* t1 = ba */ + "mulu %[t1], %[b] \n" /* a * d */ + "swap.w %[b], %[t3] \n" /* t3 = dc */ + "sts macl, %[t2] \n" /* t2 = a * d */ + "mulu %[t1], %[t3] \n" /* a * c */ + "sts macl, %[r] \n" /* hi = a * c */ + "mulu %[a], %[t3] \n" /* b * c */ + "clrt \n" + "sts macl, %[t3] \n" /* t3 = b * c */ + "addc %[t2], %[t3] \n" /* t3 += t2, carry -> t2 */ + "movt %[t2] \n" + "mulu %[a], %[b] \n" /* b * d */ + "mov %[t3], %[t1] \n" /* t2t3 <<= 16 */ + "xtrct %[t2], %[t1] \n" + "mov %[t1], %[t2] \n" + "shll16 %[t3] \n" + "sts macl, %[t1] \n" /* lo = b * d */ + "clrt \n" /* hi.lo += t2t3 */ + "addc %[t3], %[t1] \n" + "addc %[t2], %[r] \n" + : /* outputs */ + [r] "=&r"(r), + [t1]"=&r"(t1), + [t2]"=&r"(t2), + [t3]"=&r"(t3) + : /* inputs */ + [a] "r" (a), + [b] "r" (b) + ); + return r; +} +#define SC_MUL(x, y) sc_mul32(x, y) +#define SC_MUL_INIT +#define SC_MUL_END #endif #ifndef SC_SHIFT -- cgit v1.2.3