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api change: renamed cx16.push/pop_vera_context() to save/restore_vera_context()

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this better reflects its capability because it doesn't use a stack, only a single buffer
This commit is contained in:
Irmen de Jong 2023-04-17 23:37:15 +02:00
parent d01a26ec61
commit a296d26328
3 changed files with 15 additions and 14 deletions
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5
compiler/res/prog8lib/cx16/psg.p8
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@ -104,6 +104,7 @@ psg {
; you have to call this routine every 1/60th second, for example from your vsync irq handler,
; or just install this routine as the only irq handler if you don't have to do other things there.
; Example: cx16.set_irq(&psg.envelopes_irq, true)
; NOTE: this routine calls save/restore_vera_context() for you, don't nest this!
; cx16.r0 = the volume word (volume scaled by 256)
; cx16.r1L = the voice number
@ -148,7 +149,7 @@ psg {
}
; set new volumes of all 16 voices, using vera stride of 4
cx16.push_vera_context()
cx16.save_vera_context()
cx16.VERA_CTRL = 0
cx16.VERA_ADDR_L = $c2
cx16.VERA_ADDR_M = $f9
@ -160,7 +161,7 @@ psg {
for cx16.r1L in 0 to 15 {
cx16.VERA_DATA0 = cx16.VERA_DATA1 & %11000000 | msb(envelope_volumes[cx16.r1L])
}
cx16.pop_vera_context()
cx16.restore_vera_context()
popw(cx16.r9)
pop(cx16.r2L)
pop(cx16.r1L)

20
compiler/res/prog8lib/cx16/syslib.p8
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@ -786,7 +786,7 @@ IRQ_SCRATCH_ZPWORD2 .word 0
}}
}
asmsub push_vera_context() clobbers(A) {
asmsub save_vera_context() clobbers(A) {
; -- use this at the start of your IRQ handler if it uses Vera registers, to save the state
%asm {{
; note cannot store this on cpu hardware stack because this gets called as a subroutine
@ -813,24 +813,24 @@ _vera_storage: .byte 0,0,0,0,0,0,0,0
}}
}
asmsub pop_vera_context() clobbers(A) {
asmsub restore_vera_context() clobbers(A) {
; -- use this at the end of your IRQ handler if it uses Vera registers, to restore the state
%asm {{
lda cx16.push_vera_context._vera_storage+7
lda cx16.save_vera_context._vera_storage+7
sta cx16.VERA_CTRL
lda cx16.push_vera_context._vera_storage+6
lda cx16.save_vera_context._vera_storage+6
sta cx16.VERA_ADDR_H
lda cx16.push_vera_context._vera_storage+5
lda cx16.save_vera_context._vera_storage+5
sta cx16.VERA_ADDR_M
lda cx16.push_vera_context._vera_storage+4
lda cx16.save_vera_context._vera_storage+4
sta cx16.VERA_ADDR_L
lda cx16.push_vera_context._vera_storage+3
lda cx16.save_vera_context._vera_storage+3
sta cx16.VERA_CTRL
lda cx16.push_vera_context._vera_storage+2
lda cx16.save_vera_context._vera_storage+2
sta cx16.VERA_ADDR_H
lda cx16.push_vera_context._vera_storage+1
lda cx16.save_vera_context._vera_storage+1
sta cx16.VERA_ADDR_M
lda cx16.push_vera_context._vera_storage+0
lda cx16.save_vera_context._vera_storage+0
sta cx16.VERA_ADDR_L
rts
}}

4
docs/source/targetsystem.rst
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@ -162,9 +162,9 @@ The Commander X16 syslib does provides two additional routines that should be us
They take care of saving and restoring the Vera state of the interrupted main program, otherwise the IRQ handler's manipulation
will corrupt any Vera operations that were going on in the main program. The routines are::
cx16.push_vera_context()
cx16.save_vera_context()
; ... do your work that uses vera here...
cx16.pop_vera_context()
cx16.restore_vera_context()
.. caution::
The Commander X16's 16 'virtual registers' R0-R15 are located in zeropage and *are not preserved* in the IRQ handler!