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Apply shorthand Assembler macros

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This commit is contained in:
Scott Lahteine
2018-05-08 05:10:27 -05:00
parent d1b619be52
commit 0436e16fb2
9 changed files with 864 additions and 861 deletions
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454
Marlin/src/module/planner.cpp
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@ -409,7 +409,7 @@ void Planner::init() {
// %8:%7:%6 = interval
// r31:r30: MUST be those registers, and they must point to the inv_tab
" clr %13" "\n\t" // %13 = 0
A("clr %13") // %13 = 0
// Now we must compute
// result = 0xFFFFFF / d
@ -421,122 +421,122 @@ void Planner::init() {
// use Newton-Raphson for the calculation, and will strive to get way less cycles
// for the same result - Using C division, it takes 500cycles to complete .
" clr %3" "\n\t" // idx = 0
" mov %14,%6" "\n\t"
" mov %15,%7" "\n\t"
" mov %16,%8" "\n\t" // nr = interval
" tst %16" "\n\t" // nr & 0xFF0000 == 0 ?
" brne 2f" "\n\t" // No, skip this
" mov %16,%15" "\n\t"
" mov %15,%14" "\n\t" // nr <<= 8, %14 not needed
" subi %3,-8" "\n\t" // idx += 8
" tst %16" "\n\t" // nr & 0xFF0000 == 0 ?
" brne 2f" "\n\t" // No, skip this
" mov %16,%15" "\n\t" // nr <<= 8, %14 not needed
" clr %15" "\n\t" // We clear %14
" subi %3,-8" "\n\t" // idx += 8
A("clr %3") // idx = 0
A("mov %14,%6")
A("mov %15,%7")
A("mov %16,%8") // nr = interval
A("tst %16") // nr & 0xFF0000 == 0 ?
A("brne 2f") // No, skip this
A("mov %16,%15")
A("mov %15,%14") // nr <<= 8, %14 not needed
A("subi %3,-8") // idx += 8
A("tst %16") // nr & 0xFF0000 == 0 ?
A("brne 2f") // No, skip this
A("mov %16,%15") // nr <<= 8, %14 not needed
A("clr %15") // We clear %14
A("subi %3,-8") // idx += 8
// here %16 != 0 and %16:%15 contains at least 9 MSBits, or both %16:%15 are 0
"2:" "\n\t"
" cpi %16,0x10" "\n\t" // (nr & 0xf00000) == 0 ?
" brcc 3f" "\n\t" // No, skip this
" swap %15" "\n\t" // Swap nibbles
" swap %16" "\n\t" // Swap nibbles. Low nibble is 0
" mov %14, %15" "\n\t"
" andi %14,0x0f" "\n\t" // Isolate low nibble
" andi %15,0xf0" "\n\t" // Keep proper nibble in %15
" or %16, %14" "\n\t" // %16:%15 <<= 4
" subi %3,-4" "\n\t" // idx += 4
L("2")
A("cpi %16,0x10") // (nr & 0xF00000) == 0 ?
A("brcc 3f") // No, skip this
A("swap %15") // Swap nibbles
A("swap %16") // Swap nibbles. Low nibble is 0
A("mov %14, %15")
A("andi %14,0x0F") // Isolate low nibble
A("andi %15,0xF0") // Keep proper nibble in %15
A("or %16, %14") // %16:%15 <<= 4
A("subi %3,-4") // idx += 4
"3:" "\n\t"
" cpi %16,0x40" "\n\t" // (nr & 0xc00000) == 0 ?
" brcc 4f" "\n\t" // No, skip this
" add %15,%15" "\n\t"
" adc %16,%16" "\n\t"
" add %15,%15" "\n\t"
" adc %16,%16" "\n\t" // %16:%15 <<= 2
" subi %3,-2" "\n\t" // idx += 2
L("3")
A("cpi %16,0x40") // (nr & 0xC00000) == 0 ?
A("brcc 4f") // No, skip this
A("add %15,%15")
A("adc %16,%16")
A("add %15,%15")
A("adc %16,%16") // %16:%15 <<= 2
A("subi %3,-2") // idx += 2
"4:" "\n\t"
" cpi %16,0x80" "\n\t" // (nr & 0x800000) == 0 ?
" brcc 5f" "\n\t" // No, skip this
" add %15,%15" "\n\t"
" adc %16,%16" "\n\t" // %16:%15 <<= 1
" inc %3" "\n\t" // idx += 1
L("4")
A("cpi %16,0x80") // (nr & 0x800000) == 0 ?
A("brcc 5f") // No, skip this
A("add %15,%15")
A("adc %16,%16") // %16:%15 <<= 1
A("inc %3") // idx += 1
// Now %16:%15 contains its MSBit set to 1, or %16:%15 is == 0. We are now absolutely sure
// we have at least 9 MSBits available to enter the initial estimation table
"5:" "\n\t"
" add %15,%15" "\n\t"
" adc %16,%16" "\n\t" // %16:%15 = tidx = (nr <<= 1), we lose the top MSBit (always set to 1, %16 is the index into the inverse table)
" add r30,%16" "\n\t" // Only use top 8 bits
" adc r31,%13" "\n\t" // r31:r30 = inv_tab + (tidx)
" lpm %14, Z" "\n\t" // %14 = inv_tab[tidx]
" ldi %15, 1" "\n\t" // %15 = 1 %15:%14 = inv_tab[tidx] + 256
L("5")
A("add %15,%15")
A("adc %16,%16") // %16:%15 = tidx = (nr <<= 1), we lose the top MSBit (always set to 1, %16 is the index into the inverse table)
A("add r30,%16") // Only use top 8 bits
A("adc r31,%13") // r31:r30 = inv_tab + (tidx)
A("lpm %14, Z") // %14 = inv_tab[tidx]
A("ldi %15, 1") // %15 = 1 %15:%14 = inv_tab[tidx] + 256
// We must scale the approximation to the proper place
" clr %16" "\n\t" // %16 will always be 0 here
" subi %3,8" "\n\t" // idx == 8 ?
" breq 6f" "\n\t" // yes, no need to scale
" brcs 7f" "\n\t" // If C=1, means idx < 8, result was negative!
A("clr %16") // %16 will always be 0 here
A("subi %3,8") // idx == 8 ?
A("breq 6f") // yes, no need to scale
A("brcs 7f") // If C=1, means idx < 8, result was negative!
// idx > 8, now %3 = idx - 8. We must perform a left shift. idx range:[1-8]
" sbrs %3,0" "\n\t" // shift by 1bit position?
" rjmp 8f" "\n\t" // No
" add %14,%14" "\n\t"
" adc %15,%15" "\n\t" // %15:16 <<= 1
"8:" "\n\t"
" sbrs %3,1" "\n\t" // shift by 2bit position?
" rjmp 9f" "\n\t" // No
" add %14,%14" "\n\t"
" adc %15,%15" "\n\t"
" add %14,%14" "\n\t"
" adc %15,%15" "\n\t" // %15:16 <<= 1
"9:" "\n\t"
" sbrs %3,2" "\n\t" // shift by 4bits position?
" rjmp 16f" "\n\t" // No
" swap %15" "\n\t" // Swap nibbles. lo nibble of %15 will always be 0
" swap %14" "\n\t" // Swap nibbles
" mov %12,%14" "\n\t"
" andi %12,0x0f" "\n\t" // isolate low nibble
" andi %14,0xf0" "\n\t" // and clear it
" or %15,%12" "\n\t" // %15:%16 <<= 4
"16:" "\n\t"
" sbrs %3,3" "\n\t" // shift by 8bits position?
" rjmp 6f" "\n\t" // No, we are done
" mov %16,%15" "\n\t"
" mov %15,%14" "\n\t"
" clr %14" "\n\t"
" jmp 6f" "\n\t"
A("sbrs %3,0") // shift by 1bit position?
A("rjmp 8f") // No
A("add %14,%14")
A("adc %15,%15") // %15:16 <<= 1
L("8")
A("sbrs %3,1") // shift by 2bit position?
A("rjmp 9f") // No
A("add %14,%14")
A("adc %15,%15")
A("add %14,%14")
A("adc %15,%15") // %15:16 <<= 1
L("9")
A("sbrs %3,2") // shift by 4bits position?
A("rjmp 16f") // No
A("swap %15") // Swap nibbles. lo nibble of %15 will always be 0
A("swap %14") // Swap nibbles
A("mov %12,%14")
A("andi %12,0x0F") // isolate low nibble
A("andi %14,0xF0") // and clear it
A("or %15,%12") // %15:%16 <<= 4
L("16")
A("sbrs %3,3") // shift by 8bits position?
A("rjmp 6f") // No, we are done
A("mov %16,%15")
A("mov %15,%14")
A("clr %14")
A("jmp 6f")
// idx < 8, now %3 = idx - 8. Get the count of bits
"7:" "\n\t"
" neg %3" "\n\t" // %3 = -idx = count of bits to move right. idx range:[1...8]
" sbrs %3,0" "\n\t" // shift by 1 bit position ?
" rjmp 10f" "\n\t" // No, skip it
" asr %15" "\n\t" // (bit7 is always 0 here)
" ror %14" "\n\t"
"10:" "\n\t"
" sbrs %3,1" "\n\t" // shift by 2 bit position ?
" rjmp 11f" "\n\t" // No, skip it
" asr %15" "\n\t" // (bit7 is always 0 here)
" ror %14" "\n\t"
" asr %15" "\n\t" // (bit7 is always 0 here)
" ror %14" "\n\t"
"11:" "\n\t"
" sbrs %3,2" "\n\t" // shift by 4 bit position ?
" rjmp 12f" "\n\t" // No, skip it
" swap %15" "\n\t" // Swap nibbles
" andi %14, 0xf0" "\n\t" // Lose the lowest nibble
" swap %14" "\n\t" // Swap nibbles. Upper nibble is 0
" or %14,%15" "\n\t" // Pass nibble from upper byte
" andi %15, 0x0f" "\n\t" // And get rid of that nibble
"12:" "\n\t"
" sbrs %3,3" "\n\t" // shift by 8 bit position ?
" rjmp 6f" "\n\t" // No, skip it
" mov %14,%15" "\n\t"
" clr %15" "\n\t"
"6:" "\n\t" // %16:%15:%14 = initial estimation of 0x1000000 / d
L("7")
A("neg %3") // %3 = -idx = count of bits to move right. idx range:[1...8]
A("sbrs %3,0") // shift by 1 bit position ?
A("rjmp 10f") // No, skip it
A("asr %15") // (bit7 is always 0 here)
A("ror %14")
L("10")
A("sbrs %3,1") // shift by 2 bit position ?
A("rjmp 11f") // No, skip it
A("asr %15") // (bit7 is always 0 here)
A("ror %14")
A("asr %15") // (bit7 is always 0 here)
A("ror %14")
L("11")
A("sbrs %3,2") // shift by 4 bit position ?
A("rjmp 12f") // No, skip it
A("swap %15") // Swap nibbles
A("andi %14, 0xF0") // Lose the lowest nibble
A("swap %14") // Swap nibbles. Upper nibble is 0
A("or %14,%15") // Pass nibble from upper byte
A("andi %15, 0x0F") // And get rid of that nibble
L("12")
A("sbrs %3,3") // shift by 8 bit position ?
A("rjmp 6f") // No, skip it
A("mov %14,%15")
A("clr %15")
L("6") // %16:%15:%14 = initial estimation of 0x1000000 / d
// Now, we must refine the estimation present on %16:%15:%14 using 1 iteration
// of Newton-Raphson. As it has a quadratic convergence, 1 iteration is enough
@ -549,36 +549,36 @@ void Planner::init() {
// %3:%2:%1:%0 = working accumulator
// Compute 1<<25 - x*d. Result should never exceed 25 bits and should always be positive
" clr %0" "\n\t"
" clr %1" "\n\t"
" clr %2" "\n\t"
" ldi %3,2" "\n\t" // %3:%2:%1:%0 = 0x2000000
" mul %6,%14" "\n\t" // r1:r0 = LO(d) * LO(x)
" sub %0,r0" "\n\t"
" sbc %1,r1" "\n\t"
" sbc %2,%13" "\n\t"
" sbc %3,%13" "\n\t" // %3:%2:%1:%0 -= LO(d) * LO(x)
" mul %7,%14" "\n\t" // r1:r0 = MI(d) * LO(x)
" sub %1,r0" "\n\t"
" sbc %2,r1" "\n\t"
" sbc %3,%13" "\n\t" // %3:%2:%1:%0 -= MI(d) * LO(x) << 8
" mul %8,%14" "\n\t" // r1:r0 = HI(d) * LO(x)
" sub %2,r0" "\n\t"
" sbc %3,r1" "\n\t" // %3:%2:%1:%0 -= MIL(d) * LO(x) << 16
" mul %6,%15" "\n\t" // r1:r0 = LO(d) * MI(x)
" sub %1,r0" "\n\t"
" sbc %2,r1" "\n\t"
" sbc %3,%13" "\n\t" // %3:%2:%1:%0 -= LO(d) * MI(x) << 8
" mul %7,%15" "\n\t" // r1:r0 = MI(d) * MI(x)
" sub %2,r0" "\n\t"
" sbc %3,r1" "\n\t" // %3:%2:%1:%0 -= MI(d) * MI(x) << 16
" mul %8,%15" "\n\t" // r1:r0 = HI(d) * MI(x)
" sub %3,r0" "\n\t" // %3:%2:%1:%0 -= MIL(d) * MI(x) << 24
" mul %6,%16" "\n\t" // r1:r0 = LO(d) * HI(x)
" sub %2,r0" "\n\t"
" sbc %3,r1" "\n\t" // %3:%2:%1:%0 -= LO(d) * HI(x) << 16
" mul %7,%16" "\n\t" // r1:r0 = MI(d) * HI(x)
" sub %3,r0" "\n\t" // %3:%2:%1:%0 -= MI(d) * HI(x) << 24
A("clr %0")
A("clr %1")
A("clr %2")
A("ldi %3,2") // %3:%2:%1:%0 = 0x2000000
A("mul %6,%14") // r1:r0 = LO(d) * LO(x)
A("sub %0,r0")
A("sbc %1,r1")
A("sbc %2,%13")
A("sbc %3,%13") // %3:%2:%1:%0 -= LO(d) * LO(x)
A("mul %7,%14") // r1:r0 = MI(d) * LO(x)
A("sub %1,r0")
A("sbc %2,r1" )
A("sbc %3,%13") // %3:%2:%1:%0 -= MI(d) * LO(x) << 8
A("mul %8,%14") // r1:r0 = HI(d) * LO(x)
A("sub %2,r0")
A("sbc %3,r1") // %3:%2:%1:%0 -= MIL(d) * LO(x) << 16
A("mul %6,%15") // r1:r0 = LO(d) * MI(x)
A("sub %1,r0")
A("sbc %2,r1")
A("sbc %3,%13") // %3:%2:%1:%0 -= LO(d) * MI(x) << 8
A("mul %7,%15") // r1:r0 = MI(d) * MI(x)
A("sub %2,r0")
A("sbc %3,r1") // %3:%2:%1:%0 -= MI(d) * MI(x) << 16
A("mul %8,%15") // r1:r0 = HI(d) * MI(x)
A("sub %3,r0") // %3:%2:%1:%0 -= MIL(d) * MI(x) << 24
A("mul %6,%16") // r1:r0 = LO(d) * HI(x)
A("sub %2,r0")
A("sbc %3,r1") // %3:%2:%1:%0 -= LO(d) * HI(x) << 16
A("mul %7,%16") // r1:r0 = MI(d) * HI(x)
A("sub %3,r0") // %3:%2:%1:%0 -= MI(d) * HI(x) << 24
// %3:%2:%1:%0 = (1<<25) - x*d [169]
// We need to multiply that result by x, and we are only interested in the top 24bits of that multiply
@ -588,62 +588,62 @@ void Planner::init() {
// %13 = 0
// result = %11:%10:%9:%5:%4
" mul %14,%0" "\n\t" // r1:r0 = LO(x) * LO(acc)
" mov %4,r1" "\n\t"
" clr %5" "\n\t"
" clr %9" "\n\t"
" clr %10" "\n\t"
" clr %11" "\n\t" // %11:%10:%9:%5:%4 = LO(x) * LO(acc) >> 8
" mul %15,%0" "\n\t" // r1:r0 = MI(x) * LO(acc)
" add %4,r0" "\n\t"
" adc %5,r1" "\n\t"
" adc %9,%13" "\n\t"
" adc %10,%13" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * LO(acc)
" mul %16,%0" "\n\t" // r1:r0 = HI(x) * LO(acc)
" add %5,r0" "\n\t"
" adc %9,r1" "\n\t"
" adc %10,%13" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * LO(acc) << 8
A("mul %14,%0") // r1:r0 = LO(x) * LO(acc)
A("mov %4,r1")
A("clr %5")
A("clr %9")
A("clr %10")
A("clr %11") // %11:%10:%9:%5:%4 = LO(x) * LO(acc) >> 8
A("mul %15,%0") // r1:r0 = MI(x) * LO(acc)
A("add %4,r0")
A("adc %5,r1")
A("adc %9,%13")
A("adc %10,%13")
A("adc %11,%13") // %11:%10:%9:%5:%4 += MI(x) * LO(acc)
A("mul %16,%0") // r1:r0 = HI(x) * LO(acc)
A("add %5,r0")
A("adc %9,r1")
A("adc %10,%13")
A("adc %11,%13") // %11:%10:%9:%5:%4 += MI(x) * LO(acc) << 8
" mul %14,%1" "\n\t" // r1:r0 = LO(x) * MIL(acc)
" add %4,r0" "\n\t"
" adc %5,r1" "\n\t"
" adc %9,%13" "\n\t"
" adc %10,%13" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 = LO(x) * MIL(acc)
" mul %15,%1" "\n\t" // r1:r0 = MI(x) * MIL(acc)
" add %5,r0" "\n\t"
" adc %9,r1" "\n\t"
" adc %10,%13" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * MIL(acc) << 8
" mul %16,%1" "\n\t" // r1:r0 = HI(x) * MIL(acc)
" add %9,r0" "\n\t"
" adc %10,r1" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * MIL(acc) << 16
A("mul %14,%1") // r1:r0 = LO(x) * MIL(acc)
A("add %4,r0")
A("adc %5,r1")
A("adc %9,%13")
A("adc %10,%13")
A("adc %11,%13") // %11:%10:%9:%5:%4 = LO(x) * MIL(acc)
A("mul %15,%1") // r1:r0 = MI(x) * MIL(acc)
A("add %5,r0")
A("adc %9,r1")
A("adc %10,%13")
A("adc %11,%13") // %11:%10:%9:%5:%4 += MI(x) * MIL(acc) << 8
A("mul %16,%1") // r1:r0 = HI(x) * MIL(acc)
A("add %9,r0")
A("adc %10,r1")
A("adc %11,%13") // %11:%10:%9:%5:%4 += MI(x) * MIL(acc) << 16
" mul %14,%2" "\n\t" // r1:r0 = LO(x) * MIH(acc)
" add %5,r0" "\n\t"
" adc %9,r1" "\n\t"
" adc %10,%13" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 = LO(x) * MIH(acc) << 8
" mul %15,%2" "\n\t" // r1:r0 = MI(x) * MIH(acc)
" add %9,r0" "\n\t"
" adc %10,r1" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * MIH(acc) << 16
" mul %16,%2" "\n\t" // r1:r0 = HI(x) * MIH(acc)
" add %10,r0" "\n\t"
" adc %11,r1" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * MIH(acc) << 24
A("mul %14,%2") // r1:r0 = LO(x) * MIH(acc)
A("add %5,r0")
A("adc %9,r1")
A("adc %10,%13")
A("adc %11,%13") // %11:%10:%9:%5:%4 = LO(x) * MIH(acc) << 8
A("mul %15,%2") // r1:r0 = MI(x) * MIH(acc)
A("add %9,r0")
A("adc %10,r1")
A("adc %11,%13") // %11:%10:%9:%5:%4 += MI(x) * MIH(acc) << 16
A("mul %16,%2") // r1:r0 = HI(x) * MIH(acc)
A("add %10,r0")
A("adc %11,r1") // %11:%10:%9:%5:%4 += MI(x) * MIH(acc) << 24
" mul %14,%3" "\n\t" // r1:r0 = LO(x) * HI(acc)
" add %9,r0" "\n\t"
" adc %10,r1" "\n\t"
" adc %11,%13" "\n\t" // %11:%10:%9:%5:%4 = LO(x) * HI(acc) << 16
" mul %15,%3" "\n\t" // r1:r0 = MI(x) * HI(acc)
" add %10,r0" "\n\t"
" adc %11,r1" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * HI(acc) << 24
" mul %16,%3" "\n\t" // r1:r0 = HI(x) * HI(acc)
" add %11,r0" "\n\t" // %11:%10:%9:%5:%4 += MI(x) * HI(acc) << 32
A("mul %14,%3") // r1:r0 = LO(x) * HI(acc)
A("add %9,r0")
A("adc %10,r1")
A("adc %11,%13") // %11:%10:%9:%5:%4 = LO(x) * HI(acc) << 16
A("mul %15,%3") // r1:r0 = MI(x) * HI(acc)
A("add %10,r0")
A("adc %11,r1") // %11:%10:%9:%5:%4 += MI(x) * HI(acc) << 24
A("mul %16,%3") // r1:r0 = HI(x) * HI(acc)
A("add %11,r0") // %11:%10:%9:%5:%4 += MI(x) * HI(acc) << 32
// At this point, %11:%10:%9 contains the new estimation of x.
@ -651,54 +651,54 @@ void Planner::init() {
// (1<<24) - x*d
// %11:%10:%9 = x
// %8:%7:%6 = d = interval" "\n\t"
" ldi %3,1" "\n\t"
" clr %2" "\n\t"
" clr %1" "\n\t"
" clr %0" "\n\t" // %3:%2:%1:%0 = 0x1000000
" mul %6,%9" "\n\t" // r1:r0 = LO(d) * LO(x)
" sub %0,r0" "\n\t"
" sbc %1,r1" "\n\t"
" sbc %2,%13" "\n\t"
" sbc %3,%13" "\n\t" // %3:%2:%1:%0 -= LO(d) * LO(x)
" mul %7,%9" "\n\t" // r1:r0 = MI(d) * LO(x)
" sub %1,r0" "\n\t"
" sbc %2,r1" "\n\t"
" sbc %3,%13" "\n\t" // %3:%2:%1:%0 -= MI(d) * LO(x) << 8
" mul %8,%9" "\n\t" // r1:r0 = HI(d) * LO(x)
" sub %2,r0" "\n\t"
" sbc %3,r1" "\n\t" // %3:%2:%1:%0 -= MIL(d) * LO(x) << 16
" mul %6,%10" "\n\t" // r1:r0 = LO(d) * MI(x)
" sub %1,r0" "\n\t"
" sbc %2,r1" "\n\t"
" sbc %3,%13" "\n\t" // %3:%2:%1:%0 -= LO(d) * MI(x) << 8
" mul %7,%10" "\n\t" // r1:r0 = MI(d) * MI(x)
" sub %2,r0" "\n\t"
" sbc %3,r1" "\n\t" // %3:%2:%1:%0 -= MI(d) * MI(x) << 16
" mul %8,%10" "\n\t" // r1:r0 = HI(d) * MI(x)
" sub %3,r0" "\n\t" // %3:%2:%1:%0 -= MIL(d) * MI(x) << 24
" mul %6,%11" "\n\t" // r1:r0 = LO(d) * HI(x)
" sub %2,r0" "\n\t"
" sbc %3,r1" "\n\t" // %3:%2:%1:%0 -= LO(d) * HI(x) << 16
" mul %7,%11" "\n\t" // r1:r0 = MI(d) * HI(x)
" sub %3,r0" "\n\t" // %3:%2:%1:%0 -= MI(d) * HI(x) << 24
A("ldi %3,1")
A("clr %2")
A("clr %1")
A("clr %0") // %3:%2:%1:%0 = 0x1000000
A("mul %6,%9") // r1:r0 = LO(d) * LO(x)
A("sub %0,r0")
A("sbc %1,r1")
A("sbc %2,%13")
A("sbc %3,%13") // %3:%2:%1:%0 -= LO(d) * LO(x)
A("mul %7,%9") // r1:r0 = MI(d) * LO(x)
A("sub %1,r0")
A("sbc %2,r1")
A("sbc %3,%13") // %3:%2:%1:%0 -= MI(d) * LO(x) << 8
A("mul %8,%9") // r1:r0 = HI(d) * LO(x)
A("sub %2,r0")
A("sbc %3,r1") // %3:%2:%1:%0 -= MIL(d) * LO(x) << 16
A("mul %6,%10") // r1:r0 = LO(d) * MI(x)
A("sub %1,r0")
A("sbc %2,r1")
A("sbc %3,%13") // %3:%2:%1:%0 -= LO(d) * MI(x) << 8
A("mul %7,%10") // r1:r0 = MI(d) * MI(x)
A("sub %2,r0")
A("sbc %3,r1") // %3:%2:%1:%0 -= MI(d) * MI(x) << 16
A("mul %8,%10") // r1:r0 = HI(d) * MI(x)
A("sub %3,r0") // %3:%2:%1:%0 -= MIL(d) * MI(x) << 24
A("mul %6,%11") // r1:r0 = LO(d) * HI(x)
A("sub %2,r0")
A("sbc %3,r1") // %3:%2:%1:%0 -= LO(d) * HI(x) << 16
A("mul %7,%11") // r1:r0 = MI(d) * HI(x)
A("sub %3,r0") // %3:%2:%1:%0 -= MI(d) * HI(x) << 24
// %3:%2:%1:%0 = r = (1<<24) - x*d
// %8:%7:%6 = d = interval
// Perform the final correction
" sub %0,%6" "\n\t"
" sbc %1,%7" "\n\t"
" sbc %2,%8" "\n\t" // r -= d
" brcs 14f" "\n\t" // if ( r >= d)
A("sub %0,%6")
A("sbc %1,%7")
A("sbc %2,%8") // r -= d
A("brcs 14f") // if ( r >= d)
// %11:%10:%9 = x
" ldi %3,1" "\n\t"
" add %9,%3" "\n\t"
" adc %10,%13" "\n\t"
" adc %11,%13" "\n\t" // x++
"14:" "\n\t"
A("ldi %3,1")
A("add %9,%3")
A("adc %10,%13")
A("adc %11,%13") // x++
L("14")
// Estimation is done. %11:%10:%9 = x
" clr __zero_reg__" "\n\t" // Make C runtime happy
A("clr __zero_reg__") // Make C runtime happy
// [211 cycles total]
: "=r" (r2),
"=r" (r3),