29 br_i31_muladd_small(uint32_t *x, uint32_t z, const uint32_t *m)  in br_i31_muladd_small()  argument
34 	uint32_t a0, a1, b0, hi, g, q, tb;  in br_i31_muladd_small()  local
49 		hi = x[1] >> 1;  in br_i31_muladd_small()
50 		lo = (x[1] << 31) | z;  in br_i31_muladd_small()
51 		x[1] = br_rem(hi, lo, m[1]);  in br_i31_muladd_small()
58 	 * Principle: we estimate the quotient (x*2^31+z)/m by  in br_i31_muladd_small()
81 	 *   u-2 <= q <= u  in br_i31_muladd_small()
83 	hi = x[mlen];  in br_i31_muladd_small()
86 		memmove(x + 2, x + 1, (mlen - 1) * sizeof *x);  in br_i31_muladd_small()
87 		x[1] = z;  in br_i31_muladd_small()
91 		a0 = ((x[mlen] << (31 - mblr)) | (x[mlen - 1] >> mblr))  in br_i31_muladd_small()
93 		memmove(x + 2, x + 1, (mlen - 1) * sizeof *x);  in br_i31_muladd_small()
94 		x[1] = z;  in br_i31_muladd_small()
95 		a1 = ((x[mlen] << (31 - mblr)) | (x[mlen - 1] >> mblr))  in br_i31_muladd_small()
97 		b0 = ((m[mlen] << (31 - mblr)) | (m[mlen - 1] >> mblr))  in br_i31_muladd_small()
104 	 * -- If a0 == b0 then g == 0; we want q = 0x7FFFFFFF.  in br_i31_muladd_small()
105 	 * -- Otherwise:  in br_i31_muladd_small()
106 	 *    -- if g == 0 then we set q = 0;  in br_i31_muladd_small()
107 	 *    -- otherwise, we set q = g - 1.  in br_i31_muladd_small()
109 	 * quotient is q-1, q or q+1.  in br_i31_muladd_small()
111 	 * Take care that a0, a1 and b0 are 31-bit words, not 32-bit. We  in br_i31_muladd_small()
115 	q = MUX(EQ(a0, b0), 0x7FFFFFFF, MUX(EQ(g, 0), 0, g - 1));  in br_i31_muladd_small()
118 	 * We subtract q*m from x (with the extra high word of value 'hi').  in br_i31_muladd_small()
124 	 * 'hi' or the carry).  in br_i31_muladd_small()
137 		nxw = xw - zw;  in br_i31_muladd_small()
145 	 * If we underestimated q, then either cc < hi (one extra bit  in br_i31_muladd_small()
146 	 * beyond the top array word), or cc == hi and tb is true (no  in br_i31_muladd_small()
151 	 * cc > hi (thus a negative result). Correction is adding m once.  in br_i31_muladd_small()
153 	over = GT(cc, hi);  in br_i31_muladd_small()
154 	under = ~over & (tb | LT(cc, hi));  in br_i31_muladd_small()