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verafx.mult() and muls() now return both words of the 32 bits result.

This commit is contained in:
Irmen de Jong 2024-04-07 22:31:56 +02:00
parent 112d2d6058
commit 9de7698a5c
3 changed files with 36 additions and 31 deletions
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32
compiler/res/prog8lib/cx16/verafx.p8
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@ -111,17 +111,15 @@ verafx {
; unsigned multiplication just passes the values as signed to muls
; if you do this yourself in your call to muls, it will save a few instructions.
sub mult(uword value1, uword value2) -> uword {
; Returns the lower 16 bits of the 32 bits result,
; the upper 16 bits are stored in cx16.r0 so you can access those separately.
; It's not part of the subroutine's signature to avoid awkward use of multiple returnvalues.
return muls(value1 as word, value2 as word) as uword
inline asmsub mult(uword value1 @R0, uword value2 @R1) clobbers(X) -> uword @AY, uword @R0 {
; Returns the 32 bits unsigned result in AY and R0 (lower word, upper word).
%asm {{
jsr verafx.muls
}}
}
asmsub muls(word value1 @R0, word value2 @R1) clobbers(X) -> word @AY {
; Returns the lower 16 bits of the 32 bits result in AY,
; the upper 16 bits are stored in cx16.r0 so you can access those separately.
; It's not part of the subroutine's signature to avoid awkward use of multiple returnvalues.
asmsub muls(word value1 @R0, word value2 @R1) clobbers(X) -> word @AY, word @R0 {
; Returns the 32 bits signed result in AY and R0 (lower word, upper word).
%asm {{
lda #(2 << 1)
sta cx16.VERA_CTRL ; $9F25
@ -131,13 +129,13 @@ verafx {
lda #(6 << 1)
sta cx16.VERA_CTRL ; $9F25
lda cx16.r0
ldy cx16.r0+1
sta cx16.VERA_FX_CACHE_L ; $9F29
sty cx16.VERA_FX_CACHE_M ; $9F2A
lda cx16.r0+1
sta cx16.VERA_FX_CACHE_M ; $9F2A
lda cx16.r1
ldy cx16.r1+1
sta cx16.VERA_FX_CACHE_H ; $9F2B
sty cx16.VERA_FX_CACHE_U ; $9F2C
lda cx16.r1+1
sta cx16.VERA_FX_CACHE_U ; $9F2C
lda cx16.VERA_FX_ACCUM_RESET ; $9F29 (DCSEL=6)
; Set the ADDR0 pointer to $1f9bc and write our multiplication result there
@ -155,12 +153,12 @@ verafx {
stz cx16.VERA_DATA0 ; multiply and write out result
lda #%00010001 ; $01 with Increment 1
sta cx16.VERA_ADDR_H ; so we can read out the result
lda cx16.VERA_DATA0
lda cx16.VERA_DATA0 ; store the lower 16 bits of the result in AY
ldy cx16.VERA_DATA0
ldx cx16.VERA_DATA0 ; store the upper 16 bits of the result in r0
stx cx16.r0
ldx cx16.VERA_DATA0 ; store the upper 16 bits of the result in R0
stx cx16.r0s
ldx cx16.VERA_DATA0
stx cx16.r0+1
stx cx16.r0s+1
stz cx16.VERA_FX_CTRL ; Cache write disable
stz cx16.VERA_CTRL ; reset DCSEL
rts

4
docs/source/todo.rst
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@ -1,11 +1,9 @@
TODO
====
fix routines such as mult in verafx to return both 16-bit words of the result.
ubyte x,y compiles to more code than ubyte x + ubyte y
can we make ubyte x,y = cbm.SCREEN() work?
can we make ubyte x,y = cbm.SCREEN() work? (sugar for ubyte x,y // x,y=cbm.SCREEN() ?)
...

31
examples/test.p8
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@ -1,19 +1,28 @@
%import textio
%import verafx
%zeropage basicsafe
%option no_sysinit
main {
romsub $2000 = func1() clobbers(X) -> ubyte @A, word @R0, byte @R1
romsub $3000 = func2() clobbers(X) -> ubyte @A, uword @R0, uword @R1
romsub $4000 = func3() clobbers(X) -> ubyte @R0
sub start() {
bool flag
void cbm.GETIN()
flag, cx16.r1L = cbm.GETIN()
uword result, resulthi
result, resulthi = verafx.mult(9344, 6522)
txt.print_uwhex(resulthi, true)
txt.spc()
txt.print_uwhex(result, false)
txt.nl()
void, cx16.r0s, cx16.r1sL = func1()
void, cx16.r2, cx16.r1 = func2()
cx16.r0L = func3()
cx16.r0H = func3()
word sresult, sresulthi
sresult, sresulthi = verafx.muls(9344, -6522)
txt.print_w(sresulthi)
txt.spc()
txt.print_w(sresult)
txt.nl()
sresult, sresulthi = verafx.muls(144, -22)
txt.print_w(sresulthi)
txt.spc()
txt.print_w(sresult)
txt.nl()
}
}