hoo2/mips_fpmul
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Fix some comments

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This commit is contained in:
Christos Choutouridis 2020-04-29 17:19:50 +03:00
parent 706868cd95
commit 63b81a9496
1 changed files with 28 additions and 25 deletions
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53
fpmul.asm
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@ -2,12 +2,12 @@
.globl main .globl main
main: main:
# intro - stack-frame # intro - stack-frame
addi $sp, $sp, -8 # main addi $sp, $sp, -8 # main
sw $ra, 4($sp) sw $ra, 4($sp)
sw $fp, 0($sp) sw $fp, 0($sp)
addi $fp, $sp, 0 # stack arguments (no) addi $fp, $sp, 0 # stack arguments (no)
li $a0, 0xbf800000 # <-- test case goes here li $a0, 0xbf800000 # <-- test case goes here
li $a1, 0x3f800000 li $a1, 0x3f800000
jal multFloat jal multFloat
@ -27,18 +27,18 @@ main:
# $v0: The floating point word # $v0: The floating point word
encodeFloat: encodeFloat:
# intro - stack-frame # intro - stack-frame
addi $sp, $sp, -8 # encodeFloat addi $sp, $sp, -8 # encodeFloat
sw $ra, 4($sp) sw $ra, 4($sp)
sw $fp, 0($sp) sw $fp, 0($sp)
addi $fp, $sp, 0 # stack arguments (no) addi $fp, $sp, 0 # stack arguments (no)
sll $v0, $a0, 31 # v0 = sign << 31 sll $v0, $a0, 31 # v0 = sign << 31
addi $a1, $a1, 127 # v0 |= (exp + offset) << 23 addi $a1, $a1, 127 # v0 |= (exp + offset) << 23
sll $a1, $a1, 23 sll $a1, $a1, 23
or $v0, $v0, $a1 or $v0, $v0, $a1
li $t0, 0x7FFFFF # v0 |= (mant & 0x7FFFFF); li $t0, 0x7FFFFF # v0 |= (mant & 0x7FFFFF);
and $a2, $a2, $t0 and $a2, $a2, $t0
or $v0, $v0, $a2 or $v0, $v0, $a2
@ -49,7 +49,7 @@ encodeFloat:
jr $ra jr $ra
# #
# decodeFloat # decodeFloat(number)
# arguments # arguments
# $a0 : 32bit floating point # $a0 : 32bit floating point
# return # return
@ -81,7 +81,7 @@ decodeFloat:
jr $ra # return jr $ra # return
# #
# multFloat # multFloat(f1, f2)
# arguments # arguments
# $a0 : 32bit floating point 1 # $a0 : 32bit floating point 1
# $a1 : 32bit floating point 2 # $a1 : 32bit floating point 2
@ -100,15 +100,15 @@ multFloat:
sw $s0, 0($sp) sw $s0, 0($sp)
addi $fp, $sp, 0 # stack arguments (no) addi $fp, $sp, 0 # stack arguments (no)
move $s0, $a1 move $s0, $a1 # save 2nd argument
jal decodeFloat #[v0, v1, a1] <- [s, e, m] jal decodeFloat # decodeFloat(arg1) : [v0, v1, a1] <- [s, e, m]
move $t0, $s0 # change variable move $t0, $s0 # $s0 change variable to $t0
move $s0, $v0 move $s0, $v0 # load return values to variable regs
move $s1, $v1 move $s1, $v1
move $s2, $a1 move $s2, $a1
move $a0, $t0 # load argument 2 move $a0, $t0 # load back argument 2
jal decodeFloat # [v0, v1, a1] <- [s, e, m] jal decodeFloat # decodeFloat(arg2) : [v0, v1, a1] <- [s, e, m]
xor $s0, $s0, $v0 # sign = s1 ^ s2 xor $s0, $s0, $v0 # sign = s1 ^ s2
add $s1, $s1, $v1 # exp = e1 + e2 add $s1, $s1, $v1 # exp = e1 + e2
@ -120,25 +120,25 @@ multFloat:
li $t9, 0x8000 # if (HI & (1<<15)) li $t9, 0x8000 # if (HI & (1<<15))
and $t8, $t9, $t4 and $t8, $t9, $t4
beq $t8, $zero, _multf_l0 beq $t8, $zero, _multf_l0
# not zero # (true)not zero, 48-bits result, normalize
sll $s2, $t4, 8 # mant = HI << 8 sll $s2, $t4, 8 # mant = HI << 8
srl $t9, $t3, 24 # mant |= LOW >> (32-8) srl $t9, $t3, 24 # mant |= LOW >> (32-8)
or $s2, $s2, $t9 or $s2, $s2, $t9
addi $s1, $s1, 1 # ++exp addi $s1, $s1, 1 # ++exp, normalize
li $t9, 0x800000 # if (ml & (1<<23)), check to normalize li $t9, 0x800000 # if (ml & (1<<23)), rounding check
and $t8, $t9, $t3 and $t8, $t9, $t3
beq $t8, $zero, _multf_l0_end beq $t8, $zero, _multf_l0_end
addi $s2, $s2, 1 # ++mant addi $s2, $s2, 1 # ++mant, round-up
j _multf_l0_end j _multf_l0_end
_multf_l0: _multf_l0:
# zero # (false)zero, 47-bits result
sll $s2, $t4, 9 # mant = HI << 9 sll $s2, $t4, 9 # mant = HI << 9
srl $t9, $t3, 23 # mant |= LOW >> (32-9) srl $t9, $t3, 23 # mant |= LOW >> (32-9)
or $s2, $s2, $t9 or $s2, $s2, $t9
li $t9, 0x400000 # if (ml & (1<<22)), check to normalize li $t9, 0x400000 # if (ml & (1<<22)), rounding check
and $t8, $t9, $t3 and $t8, $t9, $t3
beq $t8, $zero, _multf_l0_end beq $t8, $zero, _multf_l0_end
addi $s2, $s2, 1 # ++mant addi $s2, $s2, 1 # ++mant, round-up
_multf_l0_end: _multf_l0_end:
move $a0, $s0 move $a0, $s0
@ -157,9 +157,12 @@ multFloat:
# #
# fprod(x,n) Calculates the product x[0]*x[1]*x[2]*...x[n-1] # fprod(vector, size)
# Calculates the product x[0] * x[1] * x[2] * ... * x[n-1] as
# Left fold of product operator on a vector of numbers - foldl(*, x)
#
# Arguments # Arguments
# $a0: Pointer to array x[] RAM # $a0: Pointer to array x[] in RAM
# $a1: Number of elements # $a1: Number of elements
# Return # Return
# $v0: The product # $v0: The product