igen: Start work on writing an instruction handler

generator.

This will make it easier in the long run to modify
instructions, add new instructions, and move the opcode
tables around.

3 files changed, 386 insertions, 0 deletions

diff --git a/igen/sux-igen/addr-modes.igen b/igen/sux-igen/addr-modes.igen
new file mode 100644
index 0000000..3780ed2
--- /dev/null
+++ b/igen/sux-igen/addr-modes.igen
@@ -0,0 +1,91 @@
+#include "utils.igen"
+
+%%
+
+/*
+am((abs|zm)[xy]?) {
+	if (am == zmx || am == absx) {
+		idx = cpu->x;
+	} else if (am == zmy || am == absy) {
+		idx = cpu->y;
+	}
+
+	if (am == abs || am == absx || am == absy) {
+		is_abs = 1;
+	}
+
+	size = ((prefix & 0xC) >> 1) | is_abs;
+	addr = read(cpu->pc, size) + idx;
+	value = read(addr, rs);
+}
+
+am((a)?ind([xy])?) {
+	if (am == indx || am == aindx) {
+		idx = cpu->x;
+		pre_idx = 1;
+	} else if (am == indy || am == aindy) {
+		idx = cpu->y;
+	}
+
+	if (am == aind || am == aindx || am == aindy) {
+		is_abs = 1;
+	}
+
+	size = ((prefix & 0xC) >> 1) | is_abs;
+
+	if (pre_idx) {
+		addr = read(read(cpu->pc + idx, size), 7);
+	} else {
+		addr = read(read(cpu->pc, size), 7) + idx;
+	}
+
+	value = read(addr, rs);
+}
+
+am(eind) {
+	addr = cpu->e;
+	value = read(addr, rs);
+}
+*/
+
+am(abs|zm([xy])?) {
+	if (am == abs) {
+		mem_type = ABS;
+	} else {
+		if (am == zmx) {
+			idx = cpu->x;
+		} else if (am == zmy) {
+			idx = cpu->y;
+		}
+		mem_type = ZM;
+	}
+	addr = read_addr(prefix, mem_type) + idx;
+	value = read(addr, rs);
+}
+
+am(ind([xy])?) {
+	if (am == indx) {
+		idx = cpu->x;
+		pre_idx = 1;
+	} else if (am == indy) {
+		idx = cpu->y;
+	}
+	mem_type = ZM;
+	addr = ind_idx_addr(prefix, mem_type, idx, pre_idx);
+	value = read(addr, rs);
+}
+
+am(rel) {
+	addr = rel_addr(prefix);
+}
+
+am(imm) {
+	value = read(cpu->pc, rs);
+	cpu->pc += rs+1;
+}
+
+am(breg) {
+	value = cpu->b;
+}
+
+%%
diff --git a/igen/sux-igen/inst.igen b/igen/sux-igen/inst.igen
new file mode 100644
index 0000000..791ad2c
--- /dev/null
+++ b/igen/sux-igen/inst.igen
@@ -0,0 +1,245 @@
+#include "utils.igen"
+#include "addr-modes.igen"
+
+%%
+
+(ad|sb|breg(in|de))c, and, (or|st|ld|t[bxy]|p[hl])a, xor, (ls|ro)[lr], mul, div, asr, cmp {
+	reg = &cpu->a;
+}
+
+(ld|st|cp|in|de|ta|p[hl])b {
+	reg = &cpu->b;
+}
+
+(ld|st|cp|in|de|t[ays]|p[hl])x {
+	reg = &cpu->x;
+}
+
+(ld|st|cp|in|de|t[ax]|p[hl])y {
+	reg = &cpu->y;
+}
+
+txs {
+	reg = &cpu->sp;
+}
+
+cps, (cl|se)[cio], clv, b(po|n[ge]|[cv][sc]|eq|r[ak]), p[hl]p {
+	reg = &cpu->ps;
+}
+
+ta[bxy] {
+	reg2 = &cpu->a;
+}
+
+tba, ~breg(div) {
+	reg2 = &cpu->b;
+}
+
+tx[ay], breg(div) {
+	reg2 = &cpu->x;
+}
+
+ty[ax] {
+	reg2 = &cpu->y;
+}
+
+tsx {
+	reg2 = &cpu->sp;
+}
+
+ld[abxy] {
+	*reg = value;
+	update_flags_nz(value);
+}
+
+st[abxy] {
+	value = *reg;
+	write(value, addr, rs);
+}
+
+(in|de)[cbxy] {
+	if (addr_mode == impl) {
+		value = *reg;
+	}
+	if (inst.match[0] == in) {
+		++value;
+	} else if (inst.match[0] == de) {
+		--value;
+	}
+	if (addr_mode != impl) {
+		msb = rs*8;
+		write(value, addr, rs);
+	} else {
+		*reg = value;
+	}
+	update_flags_nz(value);
+}
+
+ph[abxyp] {
+	if (inst == php) {
+		rs = 0;
+	}
+	push(*reg, rs);
+}
+
+pl[abxyp] {
+	if (inst == plp) {
+		rs = 0;
+	}
+	*reg = pull(rs);
+}
+
+/*
+ora, and, xor {
+	switch (inst) {
+		case and: sum = *reg & value; break;
+		case ora: sum = *reg | value; break;
+		case xor: sum = *reg ^ value; break;
+	}
+	*reg = sum;
+	update_flags_nz(sum);
+}
+*/
+
+ora {
+	sum = *reg | value;
+	*reg = sum;
+	update_flags_nz(sum);
+}
+
+and {
+	sum = *reg & value;
+	*reg = sum;
+	update_flags_nz(sum);
+}
+
+xor {
+	sum = *reg ^ value;
+	*reg = sum;
+	update_flags_nz(sum);
+}
+
+(se|cl)c {
+	cpu->ps.C = (inst == sec);
+}
+
+(se|cl)i {
+	cpu->ps.I = (inst == sei);
+}
+
+(se|cl)o {
+	if (ext == base && mode == base) {
+		cpu->ps.O = (inst == seo);
+	}
+}
+
+clv {
+	cpu->ps.V = 0;
+}
+
+cps {
+	cpu->ps = 0;
+}
+
+b(po|ng) {
+	cpu->pc = jump(addr, cpu->pc, get_flag(inst, bpo, cpu->ps.N));
+}
+
+bc[sc] {
+	cpu->pc = jump(addr, cpu->pc, get_flag(inst, bcs, cpu->ps.C));
+}
+
+b(ne|eq) {
+	cpu->pc = jump(addr, cpu->pc, get_flag(inst, beq, cpu->ps.Z));
+}
+
+bv[sc] {
+	cpu->pc = jump(addr, cpu->pc, get_flag(inst, bvs, cpu->ps.V));
+}
+
+bra, j(mp|sr) {
+	if (inst == jsr) {
+		push(cpu->pc, (rs) ? rs : 7);
+	}
+	cpu->pc = jump(addr, cpu->pc, 1);
+}
+
+intr(irq|nmi|reset), brk, wai {
+	if (inst == nmi) {
+		addr = 0xFFA0;
+	} else if (inst == reset) {
+		addr = 0xFFC0;
+	} else if (inst == irq) {
+		addr = 0xFFE0;
+	} else {
+		addr = 0xFFF0;
+	}
+
+	if (inst != reset) {
+		if (!cpu->is_wait) {
+			push(cpu->pc, 7);
+			push(cpu->ps, 0);
+			cpu->ps.I = 1;
+		}
+		cpu->is_wait = (inst == wai);
+	}
+	if (inst != wai) {
+		addr = read(addr, 7);
+		cpu->pc = jump(addr, cpu->pc, 1);
+	}
+}
+
+rt[si] {
+	if (inst == rti) {
+		cpu->ps = pull(0);
+	}
+	cpu->pc = pull(7);
+}
+
+(ad|sb)c {
+	if (inst == sbc) {
+		value = ~value;
+	}
+	*reg = adc(*reg, value, cpu->ps.C);
+}
+
+c(mp|p[bxy]) {
+	adc(*reg, ~value, 1);
+}
+
+(asr|ls[lr]) {
+	if (inst == lsl) {
+		sum = (value < msb) ? shift(*reg, value, 0, <<) : 0;
+		cpu->ps.C = (*reg >> (msb-(value+!value))) & 1;
+	} else {
+		if (inst == asr) {
+			sign = -(uint64_t)(*reg >> (msb-1)) << (msb-1)-value;
+		}
+		sum = (value < msb) ? shift(*reg, value, sign, >>) : 0;
+		cpu->ps.C = (*reg >> (value-(value != 0))) & 1;
+	}
+}
+
+ro[lr] {
+	if (inst == rol) {
+		rotate(sum, *reg, value, <<, >>, cpu->ps.C, cpu->ps.C << (value-1));
+		cpu->ps.C = (*reg >> (msb-(value+!value))) & 1;
+	} else {
+		rotate(sum, *reg, value, >>, <<, cpu->ps.C << (msb-1), cpu->ps.C << (msb-value));
+		cpu->ps.C = (*reg >> (value-(value != 0))) & 1;
+	}
+}
+
+mul {
+	*reg = mul(*reg, value);
+}
+
+div {
+	*reg = div(*reg, value, reg2);
+}
+
+t(a[bxy]|ba|x[ays]|y[ax]|sx) {
+	*reg = *reg2;
+	update_flags_nz(*reg);
+}
+%%
diff --git a/igen/sux-igen/utils.igen b/igen/sux-igen/utils.igen
new file mode 100644
index 0000000..7385117
--- /dev/null
+++ b/igen/sux-igen/utils.igen
@@ -0,0 +1,50 @@
+update_flags_nz(value) {
+	cpu->ps.N = bit(value, msb-1);
+	cpu->ps.Z = value == 0;
+}
+
+get_flag(name, match, flag) {
+	if (name == match) {
+		return flag;
+	} else {
+		return !flag;
+	}
+}
+
+jump(addr, fallback, flag) {
+	if (flag) {
+		return addr;
+	} else {
+		return fallback;
+	}
+}
+
+read(addr, size) {
+	return read_value(addr, size);
+}
+
+write(value, addr, size) {
+	write_value(value, addr, size);
+}
+
+adc(a, b, carry) {
+	sum = a + b + carry;
+	update_flags_nz(sum);
+	cpu->ps.C = sum < b;
+	cpu->ps.V = bit(a^b, msb-1) && bit(a^sum, msb-1);
+	return sum;
+}
+
+mul(a, b) {
+	sum = a * b;
+	update_flags_nz(sum);
+	cpu->ps.V = bit(a^b, msb-1) && bit(a^sum, msb-1);
+	return sum;
+}
+
+div(a, b, *rem) {
+	sum = a / b;
+	*rem = a % b;
+	update_flags_nz(sum);
+	return sum;
+}