172 lines
4.8 KiB
Forth
172 lines
4.8 KiB
Forth
# quick-n-dirty way to print out floats in hex
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# examples:
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# 0.5 = 0x3f000000 = 0011| 1111 | 0000 | 0000 | 0000 | 0000 | 0000 | 0000
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# = 0 | 01111110 | 00000000000000000000000
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# + exponent mantissa
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# = 0 | 00000000000000000000000 | 01111110
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# mantissa exponent
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# = 0 | 000000000000000000000000 | 01111110
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# zero-pad mantissa exponent
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# = +1.000000 P -01
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fn test-print-float-normal {
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var screen-on-stack: screen
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var screen/esi: (addr screen) <- address screen-on-stack
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initialize-screen screen, 5, 0x20 # 32 columns should be more than enough
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# print 0.5
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var one/eax: int <- copy 1
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var half/xmm0: float <- convert one
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var two/eax: int <- copy 2
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var two-f/xmm1: float <- convert two
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half <- divide two-f
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print-float screen, half
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#
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check-screen-row screen, 1, "1.000000P-01 ", "F - test-print-float-normal"
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}
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fn test-print-float-zero {
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var screen-on-stack: screen
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var screen/esi: (addr screen) <- address screen-on-stack
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initialize-screen screen, 5, 0x20 # 32 columns should be more than enough
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# print 0
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var zero: float
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print-float screen, zero
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#
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check-screen-row screen, 1, "0 ", "F - test-print-float-zero"
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}
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fn test-print-float-negative-zero {
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var screen-on-stack: screen
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var screen/esi: (addr screen) <- address screen-on-stack
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initialize-screen screen, 5, 0x20 # 32 columns should be more than enough
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# print 0
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var n: int
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copy-to n, 0x80000000
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var negative-zero/xmm0: float <- reinterpret n
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print-float screen, negative-zero
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#
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check-screen-row screen, 1, "-0 ", "F - test-print-float-negative-zero"
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}
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fn test-print-float-infinity {
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var screen-on-stack: screen
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var screen/esi: (addr screen) <- address screen-on-stack
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initialize-screen screen, 5, 0x20 # 32 columns should be more than enough
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# print
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var n: int
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# 0|11111111|00000000000000000000000
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# 0111|1111|1000|0000|0000|0000|0000|0000
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copy-to n, 0x7f800000
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var infinity/xmm0: float <- reinterpret n
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print-float screen, infinity
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#
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check-screen-row screen, 1, "Inf ", "F - test-print-float-infinity"
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}
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fn test-print-float-negative-infinity {
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var screen-on-stack: screen
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var screen/esi: (addr screen) <- address screen-on-stack
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initialize-screen screen, 5, 0x20 # 32 columns should be more than enough
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# print
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var n: int
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copy-to n, 0xff800000
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var negative-infinity/xmm0: float <- reinterpret n
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print-float screen, negative-infinity
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#
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check-screen-row screen, 1, "-Inf ", "F - test-print-float-negative-infinity"
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}
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fn test-print-float-not-a-number {
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var screen-on-stack: screen
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var screen/esi: (addr screen) <- address screen-on-stack
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initialize-screen screen, 5, 0x20 # 32 columns should be more than enough
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# print
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var n: int
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copy-to n, 0xffffffff # exponent must be all 1's, and mantissa must be non-zero
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var negative-infinity/xmm0: float <- reinterpret n
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print-float screen, negative-infinity
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#
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check-screen-row screen, 1, "Nan ", "F - test-print-float-not-a-number"
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}
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fn print-float screen: (addr screen), n: float {
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$print-float:body: {
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# - special names
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var bits/eax: int <- reinterpret n
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compare bits, 0
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{
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break-if-!=
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print-string screen, "0"
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break $print-float:body
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}
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compare bits, 0x80000000
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{
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break-if-!=
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print-string screen, "-0"
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break $print-float:body
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}
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compare bits, 0x7f800000
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{
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break-if-!=
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print-string screen, "Inf"
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break $print-float:body
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}
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compare bits, 0xff800000
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{
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break-if-!=
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print-string screen, "-Inf"
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break $print-float:body
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}
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var exponent/ecx: int <- copy bits
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exponent <- shift-right 0x17 # 23 bits of mantissa
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exponent <- and 0xff
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compare exponent, 0xff
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{
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break-if-!=
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print-string screen, "Nan"
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break $print-float:body
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}
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# - regular numbers
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var sign/edx: int <- copy bits
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sign <- shift-right 0x1f
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{
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compare sign, 1
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break-if-!=
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print-string screen, "-"
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}
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$print-float:leading-digit: {
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# check for subnormal numbers
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compare exponent, 0
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{
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break-if-!=
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print-string screen, "0."
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exponent <- increment
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break $print-float:leading-digit
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}
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# normal numbers
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print-string screen, "1."
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}
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var mantissa/ebx: int <- copy bits
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mantissa <- and 0x7fffff
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print-int32-hex-bits screen, mantissa, 0x18
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# print exponent
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print-string screen, "P"
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exponent <- subtract 0x7f
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compare exponent, 0
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{
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break-if->=
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print-string screen, "-"
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}
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var exp-magnitude/eax: int <- abs exponent
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print-int32-hex-bits screen, exp-magnitude, 8
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}
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}
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#? fn main -> r/ebx: int {
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#? run-tests
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#? #? test-print-float-negative-zero
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#? #? print-int32-hex 0, 0
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#? #? test-print-float-normal
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#? r <- copy 0
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#? }
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