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Takes a stab at BZERO.

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This commit is contained in:
Thomas Harte 2021-10-28 18:12:46 -07:00
parent da1a69be27
commit 07facc0636
2 changed files with 39 additions and 42 deletions
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79
Machines/Amiga/Blitter.cpp
View File

@ -95,16 +95,19 @@ void Blitter::set_data(int channel, uint16_t value) {
}
uint16_t Blitter::get_status() {
LOG("Returned status of " << (height_ ? 0x8000 : 0x0000));
return height_ ? 0x8000 : 0x0000;
const uint16_t result =
(not_zero_flag_ ? 0x0000 : 0x2000) | (height_ ? 0x4000 : 0x0000);
LOG("Returned status of " << result);
return result;
}
bool Blitter::advance() {
if(!height_) return false;
not_zero_flag_ = false;
if(line_mode_) {
// As-yet unimplemented:
assert(b_ == 0xffff);
assert(b_data_ == 0xffff);
//
// Line mode.
@ -163,8 +166,10 @@ bool Blitter::advance() {
// TODO: patterned lines. Unclear what to do with the bit that comes out of b.
// Probably extend it to a full word?
c_data_ = ram_[pointer_[3] & ram_mask_];
ram_[pointer_[3] & ram_mask_] =
const uint16_t output =
apply_minterm<uint16_t>(a_data_ >> shifts_[0], b_data_, c_data_, minterms_);
ram_[pointer_[3] & ram_mask_] = output;
not_zero_flag_ |= output;
draw_ &= !one_dot_;
}
@ -215,9 +220,6 @@ bool Blitter::advance() {
// Copy mode.
// int lc = 0;
// printf("*** [%d x %d]\n", width_, height_);
// Quick hack: do the entire action atomically.
a32_ = 0;
b32_ = 0;
@ -234,51 +236,47 @@ bool Blitter::advance() {
}
a32_ = (a32_ << 16) | (a_data_ & a_mask);
// The barrel shifter shifts to the right in ascending address mode,
// but to the left othrwise
if(!one_dot_) {
a_ = uint16_t(a32_ >> shifts_[0]);
} else {
// TODO: there must be a neater solution than this.
a_ = uint16_t(
(a32_ << shifts_[0]) |
(a32_ >> (32 - shifts_[0]))
);
}
if(channel_enables_[1]) {
b_data_ = ram_[pointer_[1] & ram_mask_];
pointer_[1] += direction_;
}
b32_ = (b32_ << 16) | b_data_;
if(!one_dot_) {
b_ = uint16_t(b32_ >> shifts_[1]);
} else {
b_ = uint16_t(
(b32_ << shifts_[1]) |
(b32_ >> (32 - shifts_[1]))
);
}
if(channel_enables_[2]) {
c_data_ = ram_[pointer_[2] & ram_mask_];
pointer_[2] += direction_;
}
uint16_t a, b;
// The barrel shifter shifts to the right in ascending address mode,
// but to the left othrwise
if(!one_dot_) {
a = uint16_t(a32_ >> shifts_[0]);
b = uint16_t(b32_ >> shifts_[1]);
} else {
// TODO: there must be a neater solution than this.
a = uint16_t(
(a32_ << shifts_[0]) |
(a32_ >> (32 - shifts_[0]))
);
b = uint16_t(
(b32_ << shifts_[1]) |
(b32_ >> (32 - shifts_[1]))
);
}
const uint16_t output =
apply_minterm<uint16_t>(
a,
b,
c_data_,
minterms_);
not_zero_flag_ |= output;
if(channel_enables_[3]) {
// if(!(lc&15)) printf("\n%06x: ", pointer_[3]);
// ++lc;
ram_[pointer_[3] & ram_mask_] =
apply_minterm<uint16_t>(
a_,
b_,
c_data_,
minterms_);
// printf("%04x ", ram_[pointer_[3] & ram_mask_]);
ram_[pointer_[3] & ram_mask_] = output;
pointer_[3] += direction_;
}
}
@ -288,7 +286,6 @@ bool Blitter::advance() {
pointer_[2] += modulos_[2] * channel_enables_[2] * direction_;
pointer_[3] += modulos_[3] * channel_enables_[3] * direction_;
}
// printf("\n");
}
posit_interrupt(InterruptFlag::Blitter);

2
Machines/Amiga/Blitter.hpp
View File

@ -60,9 +60,9 @@ class Blitter: public DMADevice<4> {
uint8_t minterms_ = 0;
uint32_t a32_ = 0, b32_ = 0;
uint16_t a_data_ = 0, b_data_ = 0, c_data_ = 0;
uint16_t a_ = 0, b_ = 0;
uint32_t modulos_[4]{};
bool not_zero_flag_ = false;
};
}