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fixed the stupid thing

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This commit is contained in:
Brett Weiland 2024-04-10 22:20:55 -05:00
parent 003b0887da
commit 3d66690b70
1 changed files with 18 additions and 16 deletions
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34
booth_multiplier.py
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@ -9,15 +9,18 @@ def twos_comp(num, length):
return 0 return 0
return abs((num ^ ((1 << length) - 1)) + 1) return abs((num ^ ((1 << length) - 1)) + 1)
def logical_shiftr(num, length, times): def arithmatic_shiftr(num, length, times):
#print("SHIFT START___")
#print(bin(num))
for t in range(times): for t in range(times):
num = (num >> 1) | ((1 << length) & num) num = (num >> 1) | ((1 << length - 1) & num)
#print(bin(num))
#print("SHIFT END___")
return num return num
def arithmatic_shiftl(num, length):
if num & (1 << length - 1):
return (num << 1) | (1 << length - 1)
else:
return (num << 1) & ~(1 << length - 1)
def convert_if_twoscomp(num, length): def convert_if_twoscomp(num, length):
if num & (1 << length - 1): if num & (1 << length - 1):
return (-1 * twos_comp(num, length)) return (-1 * twos_comp(num, length))
@ -49,29 +52,28 @@ def booth(multiplier, multiplicand, length):
if op == 0b10: if op == 0b10:
result += multiplicand_twos_comp << (length + 1) result += multiplicand_twos_comp << (length + 1)
result &= (1 << (length * 2) + 1) - 1 # get rid of any overflows result &= (1 << (length * 2) + 1) - 1 # get rid of any overflows
result = logical_shiftr(result, length * 2, 1) result = arithmatic_shiftr(result, (length * 2) + 1, 1)
result = result >> 1 result = result >> 1
return result return result
def booth_mod(multiplier, multiplicand, length): def booth_mod(multiplier, multiplicand, length):
multiplicand_twos_comp = twos_comp(multiplicand, length) multiplicand |= ((1 << length - 1) & multiplicand) << 1 # extend multiplicand sign to prevent overflow when mult/sub by 2
multiplicand_twos_comp = twos_comp(multiplicand, length + 1)
result = multiplier << 1 # extended bit result = multiplier << 1 # extended bit
operations = 0 operations = 0
for i in range(int(length / 2)): for i in range(int((length) / 2)):
match result & 0b111: match result & 0b111:
case 0b010 | 0b001: # add case 0b010 | 0b001: # add
result += multiplicand << (length + 1) result += multiplicand << (length + 1)
case 0b011: # add * 2 case 0b011: # add * 2
result += multiplicand << (length + 2) # extra shift is multiplying multiplicand by 2 result += arithmatic_shiftl(multiplicand, length + 1) << (length + 1) # extra shift is multiplying multiplicand by 2
case 0b100: # sub * 2 case 0b100: # sub * 2
result += multiplicand_twos_comp << (length + 2) result += arithmatic_shiftl(multiplicand_twos_comp, length + 1) << (length + 1) # extra shift is multiplying multiplicand by 2
case 0b101 | 0b110: # sub case 0b101 | 0b110: # sub
result += multiplicand_twos_comp << (length + 1) result += multiplicand_twos_comp << (length + 1)
if result & (1 << length): result &= (1 << ((length * 2) + 2)) - 1 # get rid of any overflows
print("{}: overflow".format(bin(multiplicand))) result = arithmatic_shiftr(result, (length * 2) + 2, 2)
result &= (1 << ((length * 2) + 1)) - 1 # get rid of any overflows result = ((result | ((1 << ((length * 2) + 2)) >> 1)) & ((1 << ((length * 2) + 1)) - 1)) >> 1
result = logical_shiftr(result, length * 2, 2)
result = result >> 1
return result return result