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/*
* (C) Copyright 2011 - Franck JULLIEN <elec4fun@gmail.com>
*
* Extracted from gcc generated assembly.
*
* Multiply two quads. Hereafter, the illustration of what is going on :
*
* | r3 | r4 |
* | r5 | r6 |
* --------------------
* | r4 * r6 |
* | r3 * r6 | | +
* | r5 * r4 | | +
* | r3 * r5 | | | +
* ------------------------------------------- =
* | 64 bits result |
*
*/
.globl __muldi3
__muldi3:
/* starts with the full 64 bits mul (r4 * r6) */
l.andi r7,r4,0xffff
l.srli r8,r4,0x10
l.andi r11,r6,0xffff
l.srli r12,r6,0x10
l.mul r13,r11,r7
l.mul r11,r11,r8
l.mul r7,r12,r7
l.srli r15,r13,0x10
l.add r7,r7,r15
l.add r7,r11,r7
l.sfleu r11,r7
l.bf no_carry
l.mul r8,r12,r8
l.movhi r15,0x1
l.add r8,r8,r15
no_carry:
/* Now compute r3 * r6 */
l.mul r6,r6,r3
/* and r4 * r5 */
l.mul r4,r4,r5
/* finaly previous results and put the result in r11:r12 */
l.srli r3,r7,0x10
l.slli r7,r7,0x10
l.andi r13,r13,0xffff
l.add r8,r8,r3
l.add r11,r4,r6
l.add r12,r7,r13
l.add r11,r11,r8
l.jr r9
l.nop
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