From cc63e08130fac85712365e1d9fc6be82a6f288dc Mon Sep 17 00:00:00 2001 From: Joel Sherrill Date: Mon, 4 Oct 1999 18:40:53 +0000 Subject: Patch from Ralf Corsepius to make libnetworking a top level more independently configured package. --- c/src/lib/libnetworking/netinet/in_cksum_i386.c | 200 ------------------------ 1 file changed, 200 deletions(-) delete mode 100644 c/src/lib/libnetworking/netinet/in_cksum_i386.c (limited to 'c/src/lib/libnetworking/netinet/in_cksum_i386.c') diff --git a/c/src/lib/libnetworking/netinet/in_cksum_i386.c b/c/src/lib/libnetworking/netinet/in_cksum_i386.c deleted file mode 100644 index 0612c5a7c4..0000000000 --- a/c/src/lib/libnetworking/netinet/in_cksum_i386.c +++ /dev/null @@ -1,200 +0,0 @@ -/* - * Checksum routine for Internet Protocol family headers. - * - * This routine is very heavily used in the network - * code and should be modified for each CPU to be as fast as possible. - * - * This implementation is 386 version. - * - * $Id$ - */ - -#include /* for puts */ - -#undef ADDCARRY -#define ADDCARRY(x) if ((x) > 0xffff) (x) -= 0xffff -#define REDUCE {sum = (sum & 0xffff) + (sum >> 16); ADDCARRY(sum);} - -/* - * Thanks to gcc we don't have to guess - * which registers contain sum & w. - */ -#define ADD(n) asm("addl " #n "(%2), %0" : "=r" (sum) : "0" (sum), "r" (w)) -#define ADDC(n) asm("adcl " #n "(%2), %0" : "=r" (sum) : "0" (sum), "r" (w)) -#define LOAD(n) asm volatile("movb " #n "(%1), %0" : "=r" (junk) : "r" (w)) -#define MOP asm("adcl $0, %0" : "=r" (sum) : "0" (sum)) - -int -in_cksum(m, len) - register struct mbuf *m; - register int len; -{ - register u_short *w; - register unsigned sum = 0; - register int mlen = 0; - int byte_swapped = 0; - union { char c[2]; u_short s; } su; - - for (;m && len; m = m->m_next) { - if (m->m_len == 0) - continue; - w = mtod(m, u_short *); - if (mlen == -1) { - /* - * The first byte of this mbuf is the continuation - * of a word spanning between this mbuf and the - * last mbuf. - */ - - /* su.c[0] is already saved when scanning previous - * mbuf. sum was REDUCEd when we found mlen == -1 - */ - su.c[1] = *(u_char *)w; - sum += su.s; - w = (u_short *)((char *)w + 1); - mlen = m->m_len - 1; - len--; - } else - mlen = m->m_len; - if (len < mlen) - mlen = len; - len -= mlen; - /* - * Force to long boundary so we do longword aligned - * memory operations - */ - if (3 & (int) w) { - REDUCE; - if ((1 & (int) w) && (mlen > 0)) { - sum <<= 8; - su.c[0] = *(char *)w; - w = (u_short *)((char *)w + 1); - mlen--; - byte_swapped = 1; - } - if ((2 & (int) w) && (mlen >= 2)) { - sum += *w++; - mlen -= 2; - } - } - /* - * Advance to a 486 cache line boundary. - */ - if (4 & (int) w && mlen >= 4) { - ADD(0); - MOP; - w += 2; - mlen -= 4; - } - if (8 & (int) w && mlen >= 8) { - ADD(0); - ADDC(4); - MOP; - w += 4; - mlen -= 8; - } - /* - * Do as much of the checksum as possible 32 bits at at time. - * In fact, this loop is unrolled to make overhead from - * branches &c small. - */ - mlen -= 1; - while ((mlen -= 32) >= 0) { - u_char junk; - /* - * Add with carry 16 words and fold in the last - * carry by adding a 0 with carry. - * - * The early ADD(16) and the LOAD(32) are to load - * the next 2 cache lines in advance on 486's. The - * 486 has a penalty of 2 clock cycles for loading - * a cache line, plus whatever time the external - * memory takes to load the first word(s) addressed. - * These penalties are unavoidable. Subsequent - * accesses to a cache line being loaded (and to - * other external memory?) are delayed until the - * whole load finishes. These penalties are mostly - * avoided by not accessing external memory for - * 8 cycles after the ADD(16) and 12 cycles after - * the LOAD(32). The loop terminates when mlen - * is initially 33 (not 32) to guaranteed that - * the LOAD(32) is within bounds. - */ - ADD(16); - ADDC(0); - ADDC(4); - ADDC(8); - ADDC(12); - LOAD(32); - ADDC(20); - ADDC(24); - ADDC(28); - MOP; - w += 16; - } - mlen += 32 + 1; - if (mlen >= 32) { - ADD(16); - ADDC(0); - ADDC(4); - ADDC(8); - ADDC(12); - ADDC(20); - ADDC(24); - ADDC(28); - MOP; - w += 16; - mlen -= 32; - } - if (mlen >= 16) { - ADD(0); - ADDC(4); - ADDC(8); - ADDC(12); - MOP; - w += 8; - mlen -= 16; - } - if (mlen >= 8) { - ADD(0); - ADDC(4); - MOP; - w += 4; - mlen -= 8; - } - if (mlen == 0 && byte_swapped == 0) - continue; /* worth 1% maybe ?? */ - REDUCE; - while ((mlen -= 2) >= 0) { - sum += *w++; - } - if (byte_swapped) { - sum <<= 8; - byte_swapped = 0; - if (mlen == -1) { - su.c[1] = *(char *)w; - sum += su.s; - mlen = 0; - } else - mlen = -1; - } else if (mlen == -1) - /* - * This mbuf has odd number of bytes. - * There could be a word split betwen - * this mbuf and the next mbuf. - * Save the last byte (to prepend to next mbuf). - */ - su.c[0] = *(char *)w; - } - - if (len) - puts("cksum: out of data"); - if (mlen == -1) { - /* The last mbuf has odd # of bytes. Follow the - standard (the odd byte is shifted left by 8 bits) */ - su.c[1] = 0; - sum += su.s; - } - REDUCE; - return (~sum & 0xffff); -} -- cgit v1.2.3